"Not authorized to read private messages"

[TimmyTopHat]

I checked my e-mail today, and saw a notification telling me that I received a PM on the forums. I clicked the link to see the PM (Even though the message was already repeated in the e-mail) and send a reply, and was greeted by a notice that I'm not authorized to read PMs. "Okay," I thought, "Must be an html error. I'll just go to my profile to check it." And was greeted again by the same message. Not only that, but I apparently am not authorized to send PMs either. Why can I not perform this simple task?