Navigation Update Issues?

[98es]

So instead of paying $300 at the dealer for the navigation upgrade, I bought last years version off ebay for $20. The cd is in perfect condition and has no scratches. I followed the directions and put in into the navigation unit, and got the "DISK ERROR" message. From what I understand, the 2003 update may have had problems. I've searched and found at least one other LOC member that has had this same problem, but i'm not sure if it was ever resolved. Can anyone help me? I only have the weekend to do this, so hopefully i can get this resolved. One member in a previous post suggested copying it and then trying again, is this something i should try? It seems like such an easy fix has turned into a lost cause.... Any help would be GREATLY appreciated. Thanks!