I am experiencing that same issue I complained about last year when I used Fedora Core 3 in regards to the XMMS player suddenly losing the ability to play music.
this time, i ran it in terminal and i get this error when I attmempt to play any file"
ALSA lib pcm_dmix.c:851
snd_pcm_dmix_open) unable to create IPC shm instance
** WARNING **: alsa_setup(): Failed to open pcm device (default): Permission denied
XMMS works under OSS but sounds crappy...the ALSA driver truly is superior. Since it was a permissions error, i tried running XMMS as root. That works out fine, but I'm not sure I want to have to do it each time. not sure why suddnely this has happened, anyone have any ideas?