I upgraded to Simple Press 5 about a week ago and everything seemed fine…until I tried to add a new forum. That’s when I noticed that the Simple Press admin screens weren’t functioning properly. I could access the admin screens, but once on a page it wasn’t possible to actually do anything (create a new forum, for example). Clicking the sub-menu links did nothing, and the Ajax activity indicator was not being displayed.
It was strange because Simple Press was working fine on my development server.
Eventually I determined the problem was related to the fact that I’d removed the Twenty Eleven theme from my production server. After uploading a fresh copy of Twenty Eleven to my themes folder everything is fine.
I’m not actually using Twenty Eleven and it would be nice if it didn’t need to be installed for Simple Press to run properly. I try to keep installed themes to a minimum for security reasons.