That took care of my admin problem. I can now admin my site again, thank god. Unfortunately, I still cannot access my course which I set as wiki format. I keep getting a "course module is incorrect" error. Grrrrrrr.....
At least that is only a test course, so it is not a major problem, but I would like to fix that eventually as well.
Since you mentioned the PHP version, I checked my server, and here are the stats:
Thanks a lot for the help!