I did some Googling and found some other forums where people have been posting about this problem for over a year now. I just got my first Mac about 2 weeks ago (2.3ghz MBP) and I love it! However, I am running into this same weird issue where some sounds just seem to stop playing. The only fix thus far has been to reboot the machine. There had been suggestions such as open/close Garageband (didn't work) and also closing some coreaudio program (couldn't find that one).
Does anyone have any updates on this problem or know of a good way to fix it (aside from rebooting)?
P.S. I tried to search the forums here for a thread on this but I was unable to find one. If this is a repost, then I apologize! Thanks.