Post the code or the spot +/- about 15 lines. Maybe we can spot/suggest changes.
It's a little touchy, but I know they're working on making it completely solid when I last sent in one to them.
Blank lines above/below the M00 or M01 line can sometimes throw it off.
You may need to sprinkle in some harmless tiny motion command right before the M00 or M01 line (bump a harmless axis by a few thou for example).