Disk Problems

[Lavode]

Hi all,

I have had some instability in my system recently when I use my iPod, 
so I decided to run a little Disk First Aid.  Repairing the startup 
volume resulted in the following error:
Overlapped extent allocation (file 2886156d)

Disk First Aid completes the check, says that the volume is repaired, 
but when I run it again, I get the same error.  Any way to fix this 
problem?  The last time I had a problem like this I had to restore my 
entire startup volume from a backup, as Norton would fix the symptom, 
but not the problem.

TIA,
-Lavode