See this:
http://www.osloader.com/support.htm
I'm guessing that it is not booting the os's because the disks or partitions were rearranged. If each hard disk doesn't appear to be in the same place (same cable it was plugged into), the os's will be confused. The OSL2000 loads the os's bootloaders (XP bootscreen or GRUB), then they look around and have no idea where their stuff is. Their are many ways this could have happened. The hard drives could have been physically rearranged, or the OSL2000's features may have made the os's think things were rearranged.
Hopefully, it didn't make any significant changes. If it didn't, using the Windows XP 'fixmbr' command from the XP cd should fix the problem.