clicking on 'my messages' for PMs, I get
Database Error
"Please try again. If you come back to this error screen, report the error to an administrator. "
so i am. 8-)
The staff is well aware of the problem and, I'm told, are working to solve it.
In the mean time, if you want to send someone a message, instead of clicking the PM icon, click the e-mail icon, it should, in most cases pull up your e-mail program to send a message. However, this only works if the person you want to contact has put an e-mail address in their profile.