I have a primitive mp3 jukebox that runs 'mpg321 -o oss -z -@ big_honkin.m3u'
everything puts along just fine (for over two days actually) before I get a
message that there are no more filehandles available and it dumps out.

In the process of looking at that, I discovered the joys of the remote mode
which makes it even easier to find the problem.  'mpg321 -R -o oss dummy_param'
and then 'load'ing a couple of songs results in the following lsof snippet:

[reddirt@kiran reddirt]$ /usr/sbin/lsof | grep music
sh       1137 reddirt  255r   REG    3,2      49    32073
/home/reddirt/music_startup.sh
mpg123   1138 reddirt    3r   REG    3,9 7273485  2179082
/music/other/Suteki_da_ne_orchestral.mp3
mpg123   1138 reddirt    5r   REG    3,9 9556953  3604483
/music/various/exodus/02-my_will__dc_talk.mp3

While the music is playing, there is an additional copy of the mp3 open but
instead of 3r or 5r, it's tagged as mem (memory-mapped access I assume). 
Anyhow, I've worked around it by 'quit'ting out and restarting the process, but
I'd rather spawn the background process once and not have to do that.