PartKam gcode won't run on grbl Candle

I used MakerCam to create gcode from an svg line drawing. The gcode displays and runs on the Candle simulator but, it gives errors at most of the G2/G3 instructions.

It starts to run, goes to work origin and then to the staring point, the z goes down to a test height but then, it heads for machine home and hits the stops.

Any suggestions as to why? The gcode has a comment line "created by PartKam"

Its a small engraver using Woodpecker 3.2 and Candle .9