Product Version: NetBeans IDE 6.0 (Build 200711261600)
1196764559000_nb-groovy.zip

After installing Groovy plugin to NB 6.0, I get flowing exception when starting NB IDE:

java.lang.NoClassDefFoundError: org/netbeans/modules/groovy/gsp/editor/GspKit
	at org.netbeans.modules.groovy.gsp.GspEditorSettings.updateSettingsMap(GspEditorSettings.java:78)
	at org.netbeans.editor.Settings.getKitMapWithEvent(Settings.java:715)
	at org.netbeans.editor.Settings.getKitMap(Settings.java:682)
	at org.netbeans.editor.Settings.getAllKitMaps(Settings.java:753)
	at org.netbeans.editor.Settings.getValue(Settings.java:385)
	at org.netbeans.editor.Settings.getValue(Settings.java:351)
	at org.netbeans.modules.editor.options.MacrosMIMEOptionFile.loadSettings(MacrosMIMEOptionFile.java:99)
	at org.netbeans.modules.editor.options.BaseOptions.loadDefaultMacros(BaseOptions.java:1051)
	at org.netbeans.modules.editor.options.BaseOptions.getMacroMap(BaseOptions.java:1108)
	at org.netbeans.modules.editor.options.BaseOptions.loadXMLSettings(BaseOptions.java:1730)
	at org.netbeans.modules.editor.options.BaseOptions.updateSettingsMap(BaseOptions.java:461)
	at org.netbeans.modules.editor.options.OptionSupport$SettingsInitializer.updateSettingsMap(OptionSupport.java:265)
	at org.netbeans.editor.Settings.getKitMapWithEvent(Settings.java:715)
	at org.netbeans.editor.Settings.getKitMap(Settings.java:682)
	at org.netbeans.editor.Settings.getAllKitMaps(Settings.java:753)
	at org.netbeans.editor.Settings.getValue(Settings.java:385)
	at org.netbeans.editor.Settings.getValue(Settings.java:351)
	at org.netbeans.editor.SettingsUtil.getInteger(SettingsUtil.java:121)
	at org.netbeans.editor.SettingsUtil.getPositiveInteger(SettingsUtil.java:132)
	at org.netbeans.editor.SettingsUtil.getPositiveInteger(SettingsUtil.java:141)
	at org.netbeans.editor.BaseDocument.settingsChange(BaseDocument.java:375)
	at org.netbeans.modules.editor.NbEditorDocument.settingsChange(NbEditorDocument.java:115)
	at org.netbeans.editor.Settings.fireSettingsChange(Settings.java:668)
	at org.netbeans.editor.Settings.access$100(Settings.java:122)
	at org.netbeans.editor.Settings$1.run(Settings.java:193)
	at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:561)
[catch] at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:986)

NB IDE then seems to work in some way (I'm able to edit Groovy scripts, run it) but it throws this exception from time
to time.
When I go to Tools->Options->Editor, the exception is displayed again. After that, Tool->Options cannot be invoked
anymore, GUI has to be restarted.

In my "netbeans_default_userdir" I have org-netbeans-modules-groovy-gsp.jar and it contains
org/netbeans/modules/groovy/gsp/editor/GspKit class.