The red leg of the panel in my mobile home reads 240 volt from hot to neutral. What might be the cause of this? It's causing the light bulbs to pop, and I'm afraid to turn on any appliances
You do have an open main neutral.
Turn off the main power now and call the utility. They will check to see if the problem is on their side of things or yours. I suspect yours though.
Turn your power off now.
It's possible that someone has miswired it upstream - try checking the caravan socket. It could also be an open neutral, and you have more load on L1-N than L2-N.
What do you get from L1 (black) to neutral, and L1 to L2 (red)?
In North America, the side of the transformer leading to your house has a coil that steps down from the transmission voltage to 240V. On that leg of the coil, there's a wire that splits off in the middle, so from the the top to the middle is 120V (white-black), and from the middle to the bottom is 120V (red-white). If you want 240V, you simply use the full length of the coil from top to bottom (black-red). Sounds like that's what you've got right now., but perhaps it was miscolored or mislabeled.
Check different combinations and tell us what voltage you get from each, can you get 120V with a combination of wires?