This is something I noted with a direct out-of-the-box
Redhat 6.0 system. It has an easy fix. The version of
x11amp shipped with RH 6.0 is an alpha version; the beta is
now available (and has been for some time). The alpha
version will not play MP3 files from a vfat, msdos, iso9660,
etc. filesystem; it will only play MP3 files from a second
extended (linux native) filesystem. The beta version
currently available at the above URL fixes the bug. You may
want to create an RPM binary for the beta and make note of
the fix on the General Errata page for RH 6.0.
Works with the xmms in Raw Hide.