I had that problem too for the last few days. Couldn't post, couldn't log out, couldn't start a new thread, couldn't send a PM. Hell, couldn't even edit my profit to leave a plea for help just below my avatar. I was able to log out by deleting the necessary cookies, but then I couldn't log back in. I even tried making an alt account, but the site was having none of that either. I tell you, it's been the most frustrating thing ever.
Glad it's all been sorted.