FreeMarker template error!


get(bodyClass) failed on instance of info.magnolia.module.templatingkit.templates.pages.STKPageModel
The problematic instruction:
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==> if-else  [on line 10, column 1 in templating-kit/pages/main.ftl]
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Java backtrace for programmers:
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freemarker.template.TemplateModelException: get(bodyClass) failed on instance of info.magnolia.module.templatingkit.templates.pages.STKPageModel
	at freemarker.ext.beans.BeanModel.get(BeanModel.java:224)
	at freemarker.core.Dot._getAsTemplateModel(Dot.java:76)
	at freemarker.core.Expression.getAsTemplateModel(Expression.java:89)
	at freemarker.core.BuiltIn$has_contentBI._getAsTemplateModel(BuiltIn.java:729)
	at freemarker.core.BuiltIn$has_contentBI.isTrue(BuiltIn.java:741)
	at freemarker.core.IfBlock.accept(IfBlock.java:80)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.MixedContent.accept(MixedContent.java:92)
	at freemarker.core.Environment.visit(Environment.java:221)
	at freemarker.core.Environment.process(Environment.java:199)
	at freemarker.template.Template.process(Template.java:237)
	at info.magnolia.freemarker.FreemarkerHelper.render(FreemarkerHelper.java:155)
	at info.magnolia.rendering.renderer.FreemarkerRenderer.onRender(FreemarkerRenderer.java:85)
	at info.magnolia.rendering.renderer.AbstractRenderer.render(AbstractRenderer.java:136)
	at info.magnolia.module.templatingkit.renderers.STKRenderer.render(STKRenderer.java:74)
	at info.magnolia.rendering.engine.DefaultRenderingEngine.render(DefaultRenderingEngine.java:97)
	at info.magnolia.rendering.engine.DefaultRenderingEngine$$EnhancerByCGLIB$$bed380ac.render(<generated>)
	at info.magnolia.rendering.engine.RenderingFilter.render(RenderingFilter.java:173)
	at info.magnolia.rendering.engine.RenderingFilter.doFilter(RenderingFilter.java:113)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.rendering.model.ModelExecutionFilter.doFilter(ModelExecutionFilter.java:107)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.InterceptFilter.doFilter(InterceptFilter.java:130)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.AggregatorFilter.doFilter(AggregatorFilter.java:105)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.security.BaseSecurityFilter.doFilter(BaseSecurityFilter.java:60)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.RepositoryMappingFilter.doFilter(RepositoryMappingFilter.java:101)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.CompositeFilter.doFilter(CompositeFilter.java:67)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:77)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.CompositeFilter.doFilter(CompositeFilter.java:67)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.VirtualUriFilter.doFilter(VirtualUriFilter.java:70)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:77)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.module.cache.executor.Bypass.processCacheRequest(Bypass.java:58)
	at info.magnolia.module.cache.executor.CompositeExecutor.processCacheRequest(CompositeExecutor.java:66)
	at info.magnolia.module.cache.filter.CacheFilter.doFilter(CacheFilter.java:153)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.CompositeFilter.doFilter(CompositeFilter.java:67)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.i18n.I18nContentSupportFilter.doFilter(I18nContentSupportFilter.java:76)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.RangeSupportFilter.doFilter(RangeSupportFilter.java:86)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.security.BaseSecurityFilter.doFilter(BaseSecurityFilter.java:60)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.security.SecurityCallbackFilter.doFilter(SecurityCallbackFilter.java:86)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.security.LogoutFilter.doFilter(LogoutFilter.java:93)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.module.templatingkit.filters.SiteMergeFilter.doFilter(SiteMergeFilter.java:99)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.MultiChannelFilter.doFilter(MultiChannelFilter.java:83)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.module.cache.filter.GZipFilter.doFilter(GZipFilter.java:75)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.security.auth.login.LoginFilter.doFilter(LoginFilter.java:93)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:85)
	at info.magnolia.cms.filters.CosMultipartRequestFilter.doFilter(CosMultipartRequestFilter.java:87)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.module.devicedetection.filter.DeviceDetectionFilter.doFilter(DeviceDetectionFilter.java:73)
	at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:61)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.ContentTypeFilter.doFilter(ContentTypeFilter.java:103)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.ContextFilter.doFilter(ContextFilter.java:131)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:83)
	at info.magnolia.cms.filters.CompositeFilter.doFilter(CompositeFilter.java:67)
	at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:91)
	at info.magnolia.cms.filters.SafeDestroyMgnlFilterWrapper.doFilter(SafeDestroyMgnlFilterWrapper.java:108)
	at info.magnolia.cms.filters.MgnlFilterDispatcher.doDispatch(MgnlFilterDispatcher.java:67)
	at info.magnolia.cms.filters.MgnlMainFilter.doFilter(MgnlMainFilter.java:108)
	at info.magnolia.cms.filters.MgnlMainFilter.doFilter(MgnlMainFilter.java:94)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:298)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:859)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:588)
	at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
	at java.lang.Thread.run(Thread.java:680)
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at freemarker.ext.beans.BeansWrapper.invokeMethod(BeansWrapper.java:866)
	at freemarker.ext.beans.BeanModel.invokeThroughDescriptor(BeanModel.java:277)
	at freemarker.ext.beans.BeanModel.get(BeanModel.java:184)
	... 125 more
Caused by: net.sf.cglib.proxy.UndeclaredThrowableException: java.lang.reflect.InvocationTargetException-->null
	at info.magnolia.module.templatingkit.templates.pages.STKPage$$EnhancerByCGLIB$$12424ecb.getExtrasArea(<generated>)
	at info.magnolia.module.templatingkit.style.BodyClassResolver.resolveBodyClass(BodyClassResolver.java:105)
	at info.magnolia.module.templatingkit.templates.pages.STKPageModel.getBodyClass(STKPageModel.java:84)
	... 132 more
Caused by: java.lang.reflect.InvocationTargetException
	at sun.reflect.GeneratedMethodAccessor288.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at info.magnolia.beanmerger.ProxyBasedBeanMerger$MergeInvoker.evaluate(ProxyBasedBeanMerger.java:134)
	at info.magnolia.beanmerger.ProxyBasedBeanMerger$MergeInvoker.invoke(ProxyBasedBeanMerger.java:124)
	at org.apache.commons.proxy.factory.cglib.CglibProxyFactory$InvokerBridge.invoke(CglibProxyFactory.java:116)
	... 135 more
Caused by: java.lang.ClassCastException: info.magnolia.rendering.template.configured.ConfiguredAreaDefinition cannot be cast to info.magnolia.module.templatingkit.templates.ExtrasArea
	at info.magnolia.module.templatingkit.templates.pages.STKPage.getExtrasArea(STKPage.java:93)
	... 141 more