A couple of things which can cause this to occur:
1. admin password of system not blank
2. not using the same version of sysprep that was originally used
Thanks for the reply, but I did check both of those. I blanked the admin password before sysprepping the second time, would it matter that sysprep set the password the first time? As for the second option, I used the exact same cd I had created for the first.
Like I said, using regular sysprep instead of OSP worked, but I don't know why that would happen.