well... i think some of the problem is that are making OFP loop that over and over again, which might get it confused, all you need to do is exec. that command once.
what u maybe could do instead is, make a trigger or somethin that is synced with a bunch of waypoints for teh jeep, so when u go into the trigger, then he starts to follow the WPs....
u could also try the domove command
dude2 domove getpos dude
but the 2 commands (domove and move) probably do the same thing...