Walter claims that he recorded a video of the solution to rid the world of the Observers, on his "Betamax recorder" yet the cassettes recovered (confirmed in the next episode "The Recordist") are clearly VHS cassettes.
Walter says he recorded using a Betamax video camera. However when retrieving the tapes they were VHS.
The end of Tape One shows Walter firing the amber device at the camera. Problem is, that would mean the camera is still recording, and the tape still threaded through the recording heads of the machine, when it's released from the amber. But the tape ejects just fine when they release it from the machine.