All G2/G3 arcs specify the endpoint of the arc. The start point is the current position prior to the G2/G3.
Absolute/Incremental refers to the Center location (I=X, J=Y). For Absolute arcs, I and J specify the X and Y coordinates of the center. For incremental arcs, the center is located at X-I, Y-J, when you have G2 Xx Yy Ii Jj.
It appears that your code is using absolute arcs, and I'm guessing that Cutviewer is looking for Incremental arcs, which are more commonly used. I don't use CAMBAM, but perhaps it has an option to change to incremental.