After the last failure I created a new clean Windows SharePoint v3 site. I then added all the Microsoft templates that are present on my Internet facing site. I then restored the Internet facing site from a backup and commenced the upgrade to SharePoint Foundation 2010 beta again.
After installing the files the configuration wizard started and this time failed pretty quickly with this nasty error:
An exception of type Microsoft. SharePoint.Upgrade.SPUpgradeException was thrown. Additional exception information: One or more types failed to load. Please refer to the upgrade log for more details.
Now this is interesting, because in my last attempt (with no additional templates) I got past this stage (even though it failed later).
Whatever the result I’m going to have to dig deep into the log and start trying to work out what the problem is. If you have never done this let me tell you it ain’t much fun.