WOLips NPE whenever opening a component?

Hello there,

after a comparatively long time I've got back to my WO projects; =
meantime I've updated Eclipse and plugins more than once, so alas I =
can't quite point out which of the steps was the culprit.

Nevertheless, now whenever I try to open any component, _LOTS_ of NPEs =
occur, like this:

!ENTRY org.eclipse.e4.ui.workbench 4 0 2013-02-07 02:47:24.469
!MESSAGE=20
!STACK 0
java.lang.NullPointerException
	at =
org.objectstyle.wolips.componenteditor.part.ComponentEditorPart.getEditor(=
ComponentEditorPart.java:400)
	at =
org.eclipse.ui.part.MultiPageEditorPart.pageChange(MultiPageEditorPart.jav=
a:845)
	at =
org.objectstyle.wolips.componenteditor.part.ComponentEditorPart.pageChange=
(ComponentEditorPart.java:383)
	at =
org.objectstyle.wolips.componenteditor.part.HtmlWodTab$4.handleEvent(HtmlW=
odTab.java:138)
	at =
org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4134)
...
!ENTRY org.eclipse.e4.ui.workbench 4 0 2013-02-07 02:47:24.530
!MESSAGE=20
!STACK 0
java.lang.NullPointerException
	at =
org.objectstyle.wolips.componenteditor.part.ComponentEditorPart.getEditorI=
nput(ComponentEditorPart.java:152)
	at =
org.eclipse.ui.internal.EditorReference.getEditorInput(EditorReference.jav=
a:244)
...
!ENTRY org.eclipse.ui.workbench 4 2 2013-02-07 02:47:24.549
!MESSAGE Problems occurred when invoking code from plug-in: =
"org.eclipse.ui.workbench".
!STACK 0
java.lang.NullPointerException
	at =
org.eclipse.ui.internal.SaveAllAction.updateState(SaveAllAction.java:148)
...
!ENTRY org.eclipse.ui.workbench 4 2 2013-02-07 02:47:24.668
!MESSAGE Problems occurred when invoking code from plug-in: =
"org.eclipse.ui.workbench".
!STACK 0
java.lang.NullPointerException
	at =
org.objectstyle.wolips.componenteditor.part.ComponentEditorPart.isDirty(Co=
mponentEditorPart.java:318)
	at =
org.eclipse.ui.internal.WorkbenchPartReference.isDirty(WorkbenchPartRefere=
nce.java:643)
...

and so forth, hundreds of them.

Here's a list of my installed software versions:

  Eclipse IDE for Java Developers	1.5.1.20121004-1506	=
epp.package.java	null
  Groovy Compiler 2.0 Feature	2.8.0.xx-20130205-1700-e42	=
org.codehaus.groovy20.feature.feature.group	Codehaus.org
  Groovy-Eclipse Feature	2.8.0.xx-20130205-1700-e42	=
org.codehaus.groovy.eclipse.feature.feature.group	Codehaus.org
  JDT Core patch for Groovy-Eclipse plugin	=
2.8.0.xx-20130205-1700-e42	=
org.codehaus.groovy.jdt.patch.feature.group	Codehaus.org
  WOLips	4.2.20130127.7	=
org.objectstyle.wolips.feature.feature.group	objectstyle.org
  WOLips Goodies	4.2.20130127.7	=
org.objectstyle.wolips.goodies.feature.feature.group	objectstyle.org
  WOLips Groovy Support	4.2.20130127.7	=
org.objectstyle.wolips.groovy.feature.feature.group	objectstyle.org

I've tried to find some kind of WOLips/Eclipse-compatibility list or =
something like that, so as to be able to check which of the upgrades =
might have been the culprit; but in vain: whatever I found on =
http://wiki.wocommunity.org/display/WOL/Home and elsewhere seems =
seriously outdated -- the WOLips blog has its newest item of 2009, etc. =
The installation instructions just say "Head over to the Eclipse =
Foundation and download the latest version of Eclipse suitable for your =
OS X version", which is exactly what I did, but I do wonder which =
Eclipse version was really the latest one at the time somebody wrote =
that...

Anyway, can perhaps anybody recognize this behaviour and can help me to =
work around it? Whilst I _can_ edit my components using TextEdit, it is =
sort of inconvenient... and trying to go backward re-installing older =
versions of Eclipse and the individual features does not look like a =
good option either :(

Thanks a very big lot,
OC