I have a few different phpBB 2.0.22 message boards where I have implemented 2.0.8 of ACP. The main site I am responsible for, I have no issues with and never have. (And let me say it is a godsend, so much so that that I even got a compliment from a spammer about what a pain it was to try and post! Touching, no?)
The second forum I installed on started having issues where, when logged in to the Admin Control Panel of phpBB, I was unable to access ANY of the ACP menu options (General Settings, Inactive Userlist, Profile Options, Spam Log). I click the links, the right panel goes blank and then nothing displays... indefinitely. I thought it might be an error with the installation so, on the same box, I brought up another virgin install of phpBB 2.0.22, installed EasyMod, installed ACP and... the same error. Indefinite timeout.
I installed the same type setup again on a different server thinking it might just have been a fluke, although the host (GoDaddy) was the same and... voila. Timeout.
I'm at a loss. I did try changing the cookie name (referred to in another post in the support forums), but had no luck.