2.5 Upgrade to 3.0 in Leopard

I have a problem with my 2.5-3.0 upgrade...
My machine was an iMac that is having the dreaded graphics chip overheating problem. It's running 10.4.11, and Parallels 2.5.

I went out and bought a new Mac Mini, and used the migration assistant to migrate my users and apps from the iMac to the Mini...only to discover that version 2.5 doesn't run on Leopard. Never fear, I say, because I bought a v3.0 upgrade two years ago that I never used...still have the upgrade activation key.

So I obtained a v3.0 installer (build 5584), and thought that I could just run it, and enter my upgrade activation key. But no go! Do I need an upgrade-specific installer in order to use my upgrade key? What am I missing here?

Please advise. PMs are better, as I don't check the forums often (this is my first post, in fact). But post on the forums if others can benefit as well, though...

 

Paralles 2.5/Tiger to Parallels 3.0/Leopard Upgrade

Okay, nobody's given me tips yet...so here's my gameplan:

1. Use Target disk mode for the iMac, which is running 10.4.11. The drive is fine; it's the graphics chip that is flaky (which, fortunately, doesn't affect TDM)
2. Boot my macbook pro with the Target disk as boot
3. Upgrade my Parallels 2.5 to 3.0 in that 10.4.11 install.
4. Confirm that it runs fine...
5. Perform any necessary upgrades/maintenance (compressor, etc.).
6. Shutdown the macbook, leave the TDM running on the iMac
7. Connect the TDM to the Mac Mini running Leopard
8. Perform Migration Assistant to transfer apps and users to the Mini Leopard system

Hopefully that will go okay.
Time consuming, though! And time is of the essence...

 

So, I cloned my HD, and rebooted back into my Tiger/Parallels 2.5 install. I then upgraded my Parallels install from 2.5 to 3.0 (build 5584) using the upgrade activation key. This worked!

I then booted up the Mac Mini (Leopard), and ran Migration assistant to transfer the user files over to the new machine. Parallels 3.0 worked...

I still had some problems with Compressor, though, but my set up is usable for now...