I'm having this problem as well.  My site had already been upgraded past 3.0.13 to 3.1.0 before I discovered the problem, so I don't think that the earlier posts about changing the revision number in dnn.config is helping.  Geert's script to detect and fix the symptoms (user accounts page not displaying) works, but I have no idea how to solve the root cause.

Is there a way to fix this even though I've already upgraded to 3.1.0?  Any help would be greatly appreciated!!!