I've seen several reports of others with serial number problems. Talking to Curious Labs on the phone, one of their tech folk mentioned there may be a problem with the validation algorythm (their own database was rejecting my serialnumber, which I had cut-&-pasted from an email they'd sent to me. They acknowleged it was good, but their database wouldn't accept it). Only thing that helped me was to call them directly. Phone number is on their web site. Good Luck!