I had the same problem back in December. Wouldn't let me check in online or via the kiosk at IAD. Had to wait for an agent who asked for the credit card I used to buy the ticket, my driver's license and another form of ID. Got a blue boarding pass with Zone 3 on it even though I was 1P at the time and my MP # was clearly printed on the BP. But at least it didn't have the dreaded "SSSS" on the boarding pass.

Rip...