EXS 24 Logic Sampler Users Group

Hi. i'm having trouble with my EXS24 loading the samples from a
firewire 
drive. Some instruments are fine and load everytime from the same
drive. 
Others refuse to load and hang the drive making it necesary to turn
the drive 
off. I've scanned the drive with the project manager...there are the
trouble files. 
If I go into the edit page in the EXS and click on the audio name...I
get a path 
to the file and again there is the file. i can reload all of the
samples and save 
the instrument but when I reboot the computer I'm back to square one
with the 
trouble instruments. Scrolling through the instruments is similar to
:Load, Load 
, Load,Crash. Load, Load, Load, Load, Load ,Crash.
G4 Dual 1.25 w/ 756mg ram OSX

If anyone can make sense of this question and can help I'd appreciate
your 
thoughts on this problem.
Thanks, 
Mitch