TBird crashes on T-one 8Gig HDD

I moved my Portable Apps to an 8 GB T.One USB 2.0 HDD (http://www.tigerdirect.ca/applications/SearchTools/item-details.asp?EdpN...) some time ago and everything seemed to work well. About a week ago, Portable TBird started to crash upon application start.

Interestingly enough, I've also installed the portable version of TB for Mac OS X, and that application still works on the HDD without crashing.

I upgraded to the newest version of PTB, I downgraded to an earlier version, and finally I installed to the 1 GB Thumbdrive I used to use my portable apps on (but moved to the HDD for space and worry of flash drive fatigue) and everything runs now.

Any idea why the program is crashing on the 3,400 RPM HDD and will work on the thumbdrive?

Thanks,

David