AIRTIME 2.2.0 No Sound

maybe is a bug ,i don't know
i have installed airtime 2.2.0 in to a fresh VPS (Ubuntu 11.04 i386)
airtime plays normaly for many hours with sound but when i try to listen the stream next morning airtime looks to work properly  but with no sound
when i try  this command via SSH
sudo invoke-rc.d airtime-liquidsoap restart

Sound comes up again but disconnect all  listeners from the streaming

Any Idea?

Thanks in Advance!