[Bongle]

Here are my ideas:
1) You've got a jumper set on a jaguar that prevents it from going backwards. Try looking at the jumpers on the right side of the jaguar (marked F and R). They should both have jumpers on them. If it still doesn't work, try replacing the Jaguar. We had the same problem this weekend when a motor would only run in reverse.
2) Your battery is low and causing your cRIO to act funny.