When installing SQL Server 2008 Enterprise onto my new SQL Cluster I downloaded the media from Microsoft and dropped it onto a network share and installed it. The first node went perfectly, the second node, not so much. When I went to install on the second node I would get to the screen which asked for the Key (it is a volume license install so the key was already there) and when I clicked next it told me that the key was invalid and the installer exited.
I poked around the net a little trying to figure out how the key that I used to install 30 minutes earlier on the partner machine wasn’t valid any more. Apparently it is a known bug in the RTM setup tools. If you read through the various MSKB articles they give you a complex set of file moving to do to update the setup tools on the media.
My solution was after the failure, run the SQL Server 2008 SP 1 installer on the machine with the problem. This updates the setup tools on that machine to the newer version. Then I ran the SQL 2008 setup again and it went through without an issue.