wrong turn on shopbot

[tallyeyes]

I am the IT guy at a shop trying to turn a shopbot into a production machine. The guy that brought the machine in (from his closed shop),just added new drivers? and went they ran it in 3/4" ply (2 passes), at the end of a long radius cut it turned hard right instead of left. I checked the program at it was correct. This guy won't ask for help, so I am. What the heck happened? I know this is pretty vague, maybe a just starting point?
P.S. re-ran program in air above table and it worked.

[puzzleman20]

Try the forum at shopbottools .com. Those guys live and breathe Shopbot.