regarding olp

Dear friends, i an doing simulation in delmia for arc welding application using yaskawa dx200 mh50-20 robot, and need to do offline programming for it. robots are of yaskawa, i had generated the program but after downloading it in robot, robot is not going to exact position, to cross-check i measured the dimensions of the system which is installed but it is having 2 to 3mm shift, but my program is shifted 100 to 150 mm and not working properly? after discussing with delmia experts their opinion was that, i need an RCS that will solve my problem. So is there any one who has faced same type of problem, or had used rcs?? please help me out

and after by purchasing rcs it will really solve my problem???