With regard to your gas problem, do you have a bulkhead mounted regulator or a regulator attached to your gas bottles? There should be no reason why your water heater should not work on propane unless you have a faulty regulator attached to your gas bottle.
It may be that your igniter box is faulty and you can check this by 'shorting' the brown and black wires that come from the gas valve. That is remove the two wires from the igniter and connect the two terminals on the igniter. If the igniter starts working then it would point to a faulty switch in the gas valve.