Looks promising… but it didn’t do anything for me. I mean, I did step 3 and 4 (couldn’t find userthemes.php anywhere in my install). So it’s still not working. I really think that my issue is that somehow, wordpress isn’t installed for any of my users (the main WPMU is working but not the added install on the backend for all my users). I’m wondering if I should somehow downgrade back to WPMU 2.9?