Hi,
Looks like you have two different versions on your OS, when this happens like say you have version 3.0 and then put on version 3.1 it will come up with that error. Check your rom version, and then check and make sure that you didn't try to make up a disk for your OS because the one disk had a disk error, so you tried a disk from a different OS.
Don't know if I am clear on this description. but, sometimes when you are playing with disks, you put two different versions trying to salvage one version, well it just don't work.
