I am trying to upgrade 4.5.1 to 5.1.1. First time I got errors with 4.06 and 4.09 steps so I restored the DB and the files, made sure there were proper file permission (at least I thougt I did ). Tried again, got a few more errors. Tried to restore again and now I can't login because I get module failed to load on the login page.

Any idea how to get around this?

Thanks, I believe the problems you pointed out are very similar to what I was seeing. Then I tried to restore so I could get back to where I was and try again, but that didn't work. I now have it back to the original and will definitely use your paths to upgrade.

Getting back to the original:
I used the WinMerge method to make some comparisons. My site was 4.5.1, so I got the 4.5.1 install files and unzipped them to a new folder to compare. In the end I copied the admin folder from the 4.5.1 install and that seemed to fix the problem of getting back to my starting point.