This is a series of White Papers that have been published by Microsoft before the reveal of Sharepoint 2010 at Sharepoint Coference 2009. Microsoft SharePoint Server 2010 Upgrade Planning Microsoft SharePoint Server 2010 — Test Your Upgrade Process Microsoft SharePoint Read More
The reason for the problem is that the GUID is the same as an existing site. You could either delete the old site or create a new web application and restore in that new one.
Step 1: Check Service Pack Level The first thing to verify before you do anything is to check the service pack level of your current 2.0 SharePoint installation. I found that it was still running SP1 and had never Read More