My PowerMac G5 tower recently experienced a disaster. I was able to replace the unit with a very similar unit, and moved in my hard drive. It's working great.
I've been using an external hard drive for Time Machine backups.
I decided after moving in to the "new" G5 to hook up my external drive and do another incremental backup.
I received the error messages that are associated with a different motherboard - the backups are associated with the old logic board's MAC address.
Apparently there is a relatively easy way to fix this with Snow Leopard and later - a terminal command called tmutil.
Not so in Leopard.
I found the following thread at Mac OS X Hints, and spent quite some time reading it: http://hints.macworld.com/article.php?story=20080128003716101
I felt somewhat intimidated by all the tinkering with extended attributes, and opted to use a link from the thread which lead me to a script that would automate the process.: http://hints.macworld.com/article.php?story=20081216145458979
I ran the script, it gave no error messages, and reported that the previous backups had been succesfully inherited to the new computer and Time Machine.
I can now run Time Machine, it does incremental backups, and if I boot the computer from my Leopard DVD, I can do a full restore to various points in time.
However, the Time Machine GUI application is "broken". There is no past. The only time available is NOW, even though there have been 2 or 3 recent backups, and many before then. There is no way to roll back in time, choose a file or folder and restore it.
Summary: Time Machine is creating backups, and the Leopard DVD believes it could restore the whole hard drive with them. But the handy user interface is useless - for all users.
I am very close to doing a complete scorched earth reset and simply begin doing Time Machine all over again, just to get the user interface to work.
After some time researching deleting old Time Machine backup folder (yes, I was using a drive with other data on it); was able to do so smoothly by using TMSafetynet bypass executable, ran new total backup, then another a few hours later, and the "hall of mirrors" is back. THe GUI works!
The case is closed.