From memory, I cannot say for certain what exactly the issue was, to be honest (my personal dimms are pretty dim).  I think I wound up scrapping the upgrade altogether.  I think at the time I was also attempting to do auto-windows authentication [this is an intra/extranet project and I wanted to bypass an additional login] but eventually scrapped that as well.  I have some .net programming sort of running sidecar to the DNN installation, and something in ISS did not like my sidecar once I had attempted to change to auto-auth/login (successfully).  I am still using the windows authentication to manage content to users based on AD membership, etc, which is cool.  But sorry - no good info here.