The psf file is probably not maintained. The source code you need is
located here: http://dev.eclipse.org/svnroot/modeling/org.eclipse.mdt.papy rus/branches/0.7.X/plugins
Checkout all plugins located in "core" "uml" and "others" folders. Not
that errors may be reported in
org.eclipse.papyrus.tabbedproperties.comments if EPF is not installed,
but you can ignore or close this project.