Unexpected python crashing

Hello folks. I have been having a problem with python crashing when I run a script. I am hoping someone can suggest a way to figure out what the cause might be.

I need to copy sets of files from external drives to our server. I typically am moving about 2 TB at a time, with individual files between 10 GB and 40 GB each. With our setup (both equipment and security settings, not something I can do anything about) this takes anywhere from several hours to a couple of days. Using Windows to copy the files frequently resulted in errors/failure and a whole mess of work to figure out which files were corrupted. I wrote a script to copy the files one at a time, display info about each file, write the info to a .txt, write error info into another txt, and at the end wait for a user prompt. I know the error logging works for some types of errors (specifically, network problems).
This generally works fine, but about once a week python crashes in the middle of the transfer. My log just cuts off, and no errors are written. The error seems to come in the midst of the transfer--usually a file is left half transferred. I am using shutil.copy for the move, and it is in a try/except with a traceback. It seems to me that the problem is not so much my script as that python is just crashing, but I don't know why that would be happening. Any ideas how I can figure out what is causing python to crash out?

(python 2.6.5, WinXP)

Thanks,
Erik