The runtime error "safeAcos: Invalid argument, arg = nan" may be caused by multiple radial welds taught at the same physical point.
The overlapping points often are 3-5 points near where the welding program stopped due to the error.
To find the overlapping points, use the Move Here feature point-by-point for each point between where the program stopped and a few points before and after that. When you find a point where Move Here does not cause the robot arm to move then you've found a duplicate point and should delete it. Repeat this process to delete all duplicate points from the part.
