Hi Katharina,
I got the same error messages if I use the "FileLinkExtention" in mediawiki
1.11.1. So it´s not working under 1.11.x.
Did you have a Wiki version wich is working with it?
The extension is working fine
with mediawiki 1.10.0, but as the wiki is a
private intranet-wiki, I'm afraid, I cannot give you access to it. :-(
Cu Katharina