Error running scala-plugin as Eclipse application

Hello,
I checked out the Eclipse Plugin as explain in the wiki
(https://lampsvn.epfl.ch/trac/scala/wiki/EclipsePlugin).
I built it successfully but I have an error when I want to run it (“Run
as Eclipse Application”).

The error is:
"The org.eclipse.jdt.ui.javaElementFilters plug-in extension
"scala.tools.eclipse.javaelements.ScalaElementFilter" specifies a viewer
filter class which does not exist.
Plug-in ch.epfl.lamp.sdt.core was unable to load class
scala.tools.eclipse.javaelements.ScalaElementFilter.
scala.tools.eclipse.javaelements.ScalaElementFilter"

I tried “Project => Clean” but it changes nothing.

Any ideas?

Thanks

Johan