The problem is with plugin libxmms-flac.so - the newest version of glibc doesn't like the way FLAC initializes certain variables. There are several ways to fix it:
1. Remove the FLAC plugins from the xmms plugins folder (easiest, if you don't play any FLAC files)
2. Wait for a new version of FLAC (this issue will have been corrected) and then install it
3. Fix the offending FLAC source file, recompile and install
If you want to try #3, please see the following for details:
http://sourceforge.net/tracker/index...78&atid=113478