Steps to reproduce:

1. create two pages /f.e. main and linkedPage/
2. in main page add the paragraph with dialog of fckEdit control
3. link it with the linkedPage
4. delete the linkedPage
5. try to edit the dialog of main page, it's not rendered and the following error occurs:

2009-09-09 10:15:04,720 ERROR [Catalina].[localhost].[/magnoliaAuthor].[default]: Servlet.service() for servlet default threw exception
java.lang.NullPointerException
at java.util.regex.Matcher.getTextLength(Matcher.java:1127)
at java.util.regex.Matcher.reset(Matcher.java:284)
at java.util.regex.Matcher.<init>(Matcher.java:205)
at java.util.regex.Pattern.matcher(Pattern.java:879)
at info.magnolia.module.fckeditor.dialogs.FckEditorDialog.convertToView(FckEditorDialog.java:407)
at info.magnolia.module.fckeditor.dialogs.FckEditorDialog.drawHtml(FckEditorDialog.java:281)
at info.magnolia.cms.gui.dialog.DialogControlImpl.drawSubs(DialogControlImpl.java:322)
at info.magnolia.cms.gui.dialog.DialogControlImpl.drawHtml(DialogControlImpl.java:166)
at info.magnolia.cms.gui.dialog.DialogControlImpl.drawSubs(DialogControlImpl.java:322)
at info.magnolia.cms.gui.dialog.DialogControlImpl.drawHtml(DialogControlImpl.java:166)
at info.magnolia.module.admininterface.DialogMVCHandler.renderHtml(DialogMVCHandler.java:400)
at info.magnolia.cms.servlets.MVCServlet.doPost(MVCServlet.java:123)
at info.magnolia.cms.servlets.MVCServlet.doGet(MVCServlet.java:68)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:627)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
at info.magnolia.cms.filters.ServletDispatchingFilter.doFilter(ServletDispatchingFilter.java:164)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:84)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:84)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:84)
at info.magnolia.cms.filters.CompositeFilter.doFilter(CompositeFilter.java:64)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.filters.VirtualUriFilter.doFilter(VirtualUriFilter.java:115)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.i18n.I18nContentSupportFilter.doFilter(I18nContentSupportFilter.java:75)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.module.cache.executor.Bypass.processCacheRequest(Bypass.java:57)
at info.magnolia.module.cache.filter.CacheFilter.doFilter(CacheFilter.java:118)
at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:62)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.module.cache.filter.GZipFilter.doFilter(GZipFilter.java:82)
at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:62)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:84)
at info.magnolia.cms.filters.CosMultipartRequestFilter.doFilter(CosMultipartRequestFilter.java:87)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.security.BaseSecurityFilter.doFilter(BaseSecurityFilter.java:61)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.security.LogoutFilter.doFilter(LogoutFilter.java:88)
at info.magnolia.cms.filters.OncePerRequestAbstractMgnlFilter.doFilter(OncePerRequestAbstractMgnlFilter.java:62)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.security.auth.login.LoginFilter.doFilter(LoginFilter.java:84)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.enterprise.registration.RegistrationFilter.doFilter(RegistrationFilter.java:50)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.filters.ContentTypeFilter.doFilter(ContentTypeFilter.java:84)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.filters.ContextFilter.doFilter(ContextFilter.java:87)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlFilterChain.doFilter(MgnlFilterChain.java:82)
at info.magnolia.cms.filters.CompositeFilter.doFilter(CompositeFilter.java:64)
at info.magnolia.cms.filters.AbstractMgnlFilter.doFilter(AbstractMgnlFilter.java:70)
at info.magnolia.cms.filters.MgnlMainFilter.doFilter(MgnlMainFilter.java:96)
at info.magnolia.cms.filters.MgnlMainFilter.doFilter(MgnlMainFilter.java:199)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:174)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:875)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
at java.lang.Thread.run(Thread.java:595)

p.s. in previous versions of Magnolia the behavior was correct - the dialog window is rendered.