I have an Apple G5 with OSX 10.3 and I'm trying to upgrade to 10.5. I'm getting the error: "Missing bill of materials".
I'm relatively new to Macs so I may not be providing all the relevant information here.
I would suggest that rather than do an "Upgrade," do an "Archive and Install." At the point in the install process where you select the hard drive, there should be an Options button. Click that and you ought to be able to choose "Archive and Install" with "Preserve Users and Network Settings."
This process will simply give you a new system and won't rely on receipts to determine what items need to be updated.