System Stalls, Redirect Error, upon using FB to register

Upon using Facebook to register on our site, the system hangs after selecting, "Create My Account" --> "Select This Profile" -->"Complete Registration" the system then stalls and then returns the error "The page isn't redirecting properly". The Administrator is emailed that a new user has registered. The newly registered user is unable to do anything on the computer, even access the main site, the same error message is returned. This continues until that user is deleted from the system. Once deleted, the system returns to functioning "normally".