Character mistake: Upon hearing that Lister, Kryten, Cat and Rimmer have travelled from Albion - England - to India the woman in the market expresses surprise that they have travelled "halfway across the known world" just to buy lemons. In 23AD travelling from England to India was all the way across the known world. The Americas, Australasia and China were completely unknown at the time.
Continuity mistake: When Howard and Crawford are transported to Trojan, two of the three teleporter doors are open. When Crawford goes through the teleporter, one of the three doors close. Yet when Cat puts the resentment file into Crawford's neck, she starts shooting at everything including the teleporters, and now all the doors are open. (00:23:00 - 00:26:30)