Are you moving everything onto a computer that has the same OS as the previous one? Quite a while ago, I ran into an issue where myimpulse files would not transfer from one machine to another. Turns out that these files couldn't be transferred between WinXP (32-bit) and Vista (64-bit.) The exact quote:
You can transfer archives from one PC to another. You need to archive on the same machine type as you are targeting. For example, you need to archive on Windows XP 32-bit if you are moving to Windows XP 32-bit.
Granted, this was close to three years ago, but it sounds like you may be running into a similar problem.