When I try to upgrade from 4.4.11 to 4.5.9 using latest 1.2.4-SNAPSHOT version (magnolia-4-5-migration-1.2.4-20130724.135205-42) the migration task shows the error:

2013-07-25 15:20:08,705 INFO gnolia.migration.reporting.DefaultReportingService: Starting migration of extends definition for the following module:public-user-registration
2013-07-25 15:20:08,705 WARN info.magnolia.cms.util.ClasspathResourcesUtil : missing file: D:\GitWS\worldsteel-magnolia\worldsteel-webapp\target\classes
2013-07-25 15:20:08,847 INFO gnolia.migration.reporting.DefaultReportingService: Finishing migration of extends definition for the following module:public-user-registration
2013-07-25 15:20:08,850 ERROR info.magnolia.module.ui.ModuleManagerWebUI : Could not perform installation: info/magnolia/migration/task/module/pur/PurExtraConfigTask
java.lang.NoClassDefFoundError: info/magnolia/migration/task/module/pur/PurExtraConfigTask
at info.magnolia.module.publicuserregistration.setup.PublicUserRegistrationMigrationTask.executeExtraMigrationTask(PublicUserRegistrationMigrationTask.java:58)
at info.magnolia.migration.task.AbstractSTKRelatedModuleMigrationTask.executeTask(AbstractSTKRelatedModuleMigrationTask.java:115)
at info.magnolia.migration.task.AbstractMigrationTask.execute(AbstractMigrationTask.java:123)
at info.magnolia.module.ModuleManagerImpl.applyDeltas(ModuleManagerImpl.java:499)
at info.magnolia.module.ModuleManagerImpl.installOrUpdateModule(ModuleManagerImpl.java:481)
at info.magnolia.module.ModuleManagerImpl$1.doExec(ModuleManagerImpl.java:270)
at info.magnolia.context.MgnlContext$VoidOp.exec(MgnlContext.java:443)
at info.magnolia.context.MgnlContext$VoidOp.exec(MgnlContext.java:440)
at info.magnolia.context.MgnlContext.doInSystemContext(MgnlContext.java:403)
at info.magnolia.module.ModuleManagerImpl.performInstallOrUpdate(ModuleManagerImpl.java:264)
at info.magnolia.module.ui.ModuleManagerWebUI$2.run(ModuleManagerWebUI.java:127)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.ClassNotFoundException: info.magnolia.migration.task.module.pur.PurExtraConfigTask
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:424)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:377)
... 12 more
2013-07-25 15:20:08,864 ERROR info.magnolia.module.InstallContextImpl : > Could not perform installation: info/magnolia/migration/task/module/pur/PurExtraConfigTask
java.lang.NoClassDefFoundError: info/magnolia/migration/task/module/pur/PurExtraConfigTask
at info.magnolia.module.publicuserregistration.setup.PublicUserRegistrationMigrationTask.executeExtraMigrationTask(PublicUserRegistrationMigrationTask.java:58)
at info.magnolia.migration.task.AbstractSTKRelatedModuleMigrationTask.executeTask(AbstractSTKRelatedModuleMigrationTask.java:115)
at info.magnolia.migration.task.AbstractMigrationTask.execute(AbstractMigrationTask.java:123)
at info.magnolia.module.ModuleManagerImpl.applyDeltas(ModuleManagerImpl.java:499)
at info.magnolia.module.ModuleManagerImpl.installOrUpdateModule(ModuleManagerImpl.java:481)
at info.magnolia.module.ModuleManagerImpl$1.doExec(ModuleManagerImpl.java:270)
at info.magnolia.context.MgnlContext$VoidOp.exec(MgnlContext.java:443)
at info.magnolia.context.MgnlContext$VoidOp.exec(MgnlContext.java:440)
at info.magnolia.context.MgnlContext.doInSystemContext(MgnlContext.java:403)
at info.magnolia.module.ModuleManagerImpl.performInstallOrUpdate(ModuleManagerImpl.java:264)
at info.magnolia.module.ui.ModuleManagerWebUI$2.run(ModuleManagerWebUI.java:127)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.ClassNotFoundException: info.magnolia.migration.task.module.pur.PurExtraConfigTask
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass(SelfFirstStrategy.java:50)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:244)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:424)
at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:377)