eclipse plug-in nightly build no class files

He,

    I have just installed the nightly build of the eclipse plug-in.  I haven't changed anything on my projects, but none of those runs anymore.  All I get is:

Exception in thread "main" java.lang.NoClassDefFoundError:

When I check for *.class there are none.  So what else can I do...

Cheers,
  /nm