asterisk users - Mar 2006 - problems with MOH

hi

on a server i've installed slackware 10.2 and

Asterisk Version 1.2.4
Zaptel Version 1.2.4
Libpri Version 1.2.2

I'm experiencing problem with moh, the music is correctly started:

Started music on hold, class 'default', on channel 'Zap/1-1'

but i don't hear anything... i heard something like a
"fiiiiiiiiiiiii"
very very low

the server is without a sound card, it this the problem?

i've installed mpg123, the last version

Version 0.59r

this is my mysiconhold.conf

[default]

mode=quietmp3
directory=/var/lib/asterisk/mohmp3
application=/usr/local/bin/mpg123 -q -r 8000 -f 8192 -b 2048 --mono -s

the directory /var/lib/asterisk/mohmp3 is readable by all...