1. Sandra report. You have told us ZERO about your system and we can't begin to even guess. But if I WERE to make a guess:
2. Aforementioned Sandra report
might indicate that you are only using one hard drive, and you need a separate dedicated audio drive if you want this to work.
See the very top of the forum that says "Help us help you."
http://duc.avid.com/showthread.php?t=193637
And someone needs to make it in flashing red.