Delete all portable fragment bookmarks

Hi experts

I have a button in my dashboard that should delete all portable fragment bookmarks. I use the following script:

Bookmark.PortableFragmentBookmark.deleteAllBookmarks("OnlineCompBookmark");

The bookmarks has been created with the same group identifier "OnlineCompBookmark".

When i run the script i do not get any error messages and no bookmarks are deleted. Is this a known bug in DS 1.4 SP01? Anyone who knows a workaround?

Kind regards

Erik