NO NEED TO SHOUT!
What version of which product (MA or MA Time) are you using? Can you provide us with any more details about your set-up?
When you say the sound "cuts off", do you mean it pauses for a second or two and then resumes, or does it stop entirely (never to return)?
We use QuickTime to play a sound segment in a loop for the bubbles (it's about a 7-9 second loop). Are you experiencing any other problems with QuickTime on your system?
Are you using the built-in speaker or external speakers? If external, how are they connected to your system (sound out jack, USB)?