Can you test the leg motor. You can test it with the test board from when you tested them in the early build stages. Also check the wiring on the motor at the foot end as well, there maybe a bad connection.
Once you have checked all cables are correctly placed and pushed in firmly and you are still having a problem, then try switching the leg motor wiring around into the left leg to test to see if the motors still does not work when placed in the other leg connector.
I'm affraid it is a case of elimination.
Let me know how you get on.

Regards
Mark