Greetings!

Questions:

a) Are you running Hijack, and if so, what version?
b) What is your hard drive configuration?
c) You are using XP - are you uploading via USB or ethernet? USB is known to be buggy under XP.

Observations:

To be honest, 50 albums at a shot is not overly zealous. I have loaded huge chucks on music at a shot, and not had difficulties. The disk check running for a long time is normal - it is fsck'ing the hard drives. I am guessing you are dual drive, since it ran through twice. This is normal, as long as it is not extreme (I see fsck times of 45 minutes per drive, but that is because I am at the extreme end of things.) I suspect that you are seeing one of the following problems (you can search the BBS for more info):

a) a buggy XP / USB interface
b) an early version of Hijack without the checkpoints in place
c) a bad crimp on your hard drive cable

If you are running the developer kernel, I would reboot, drop to shell, follow the procedure for fixing hard drive problems and trying again. If you continue to see problems, post a boot log - maybe something is sick there.

If it is a bad cable, you will need to contact support for a replacement.