Audio problem: Jonesy is playing the organ. A pigeon 'flies' out the top of the organ and lands on the keys, so Jonesy picks it up and moves it, taking both his hands off the keys. Yet the music plays on.
Factual error: When Mainwaring is driving the van and Jones is in the back suffering from malaria, just after Pike shouts out that Jones has changed colour, if you look out the side window you can see a triangular road sign. These did not come into use until the 1960s.