Do a clean install.
Upgrade install is only senseful if you go frm 10.3 to 10.4 or 10.4 to 10.5. Jumping from 10.2 to 10.4 or 10.3 to 10.5 etc is not tested and is not a good idea.
So first back up everything to some other drive.
Then make sure you have enough RAM.
Then do a clean install, and then import whatever you need ver.