Usage on WebDAV share impossible, reason unknown

I already posted this on the Ubuntuforums Security Subforum, but share my problem once again here:

I'm trying to make ecryptfs work on my GMX Mediacenter share (a service quite popular in Germany). I followed the instructions to include my mediacenter share in my fstab which works pretty well. So now I'm able to connect via Secure WebDAV as a regular user (no sudo needed).

When connected, I try to create a ecryptfs transparent layer so everything saved remotely is seamlessly encrypted.

Although no error message is thrown during creation, the process fails. When entering the remote share (cd mediacenter) and performing any remote command such as "ls -la", the following error message is thrown:

~/mediacenter$ ls
ls: cannot open directory .: Invalid argument

What's wrong here?

Thanks!

addition 2010-01-30 i think the problem is not a programming error in Ubuntu's WebDAV implementation. Since filing this bug report, I have posted the error description on several forums and there were no reports from other users experiencing the same ...