Banshee shows Little box with X for every file. (Seem to be stuck loading file <filename>, so retrying)

Banshee does not play any Files.
There is an little box with a X for every File.

If i run Banshee in Terminal, i get the following error after i try to play a File:
[Warn 22:36:23.835] Seem to be stuck loading file:///home/anja/Musik/Unbekannter%20Interpret/Die%20%C3%84rzte/01%20Titelnummer%201.wma, so re-trying

Also:
Rhytmbox does not import any Files, so there might be a problem with one library or something. I dont know.

ProblemType: Bug
DistroRelease: Ubuntu 13.10
Package: libgstreamer0.10-0 0.10.36-1.2ubuntu1
ProcVersionSignature: Ubuntu 3.11.0-18.32-generic 3.11.10.4
Uname: Linux 3.11.0-18-generic x86_64
ApportVersion: 2.12.5-0ubuntu2.2
Architecture: amd64
Date: Sat Mar 15 22:37:44 2014
InstallationDate: Installed on 2014-01-26 (48 days ago)
InstallationMedia: Ubuntu 12.04.3 LTS "Precise Pangolin" - Release amd64 (20130820.1)
MarkForUpload: True
SourcePackage: gstreamer0.10
UpgradeStatus: Upgraded to saucy on 2014-03-09 (6 days ago)