We usually don't recommend doing a move and upgrade at the same time, but given that you can't do that because of the system constraints, here's the order I'd go in:
- First, follow the first 2 steps in Moving and Indigo 6 install to another Mac (you can't do step 3, but that's OK).
- Next, run the Indigo 7 installer but don't start it up.
- Lastly, look at the Upgrading from Indigo 6 instructions to make sure everything got moved over correctly.
One final thing is that it's possible your Indigo database file isn't in the normal location (which is in the Databases folder inside the Indigo 6 install folder). If you can still start up Indigo 6 on the old Mac, do that and control-click the database name in the Home Window title bar and it will show you the path to the database file. If it's not in the Databases folder, then you'll need to move it over manually (I'd put it in the Databases folder before you copy it over to the new Mac).