Please file a support ticket. Include your dxdiag and the latest PotBS log from My Documents\Pirates of the Burning Sea.
All our sound goes through the Miles library, used by like 98% of games, so it's baffling that you only have problems with us.
You might try adding
Code:
[Sound]
maxSounds=##
to pirates_local.ini, where ## is some number. The default value is 64. Play around with the value a bit, 32 would be a good start.