maybe I wasn't clear before....give us the EXACT error.
force it to happen again and then copy down word for word what it says. Just telling us "it says something about firewire or fragments" doesn't help. I need the EXACT wording. These errors are specific.
something like:
"DAE can't get audio from the disk fast enough. Your disk may be too slow or too fragmented. A firewire disk could be having trouble due to the extra firewire bandwidth or CPU load."
THAT tells me a lot more about the error than what you gave me