Same problem here. I have cGPSmapper Pro and cGPSmapper Standard. (the older version) Both are registered. When I compile same marine map .mp with the Standard version-no gaps, same map with the Pro version-gaps. I tryed the header like you did, and it helped in the chart ploter, but not in Mapsource. There I can still see the gaps. It looks like the new version is rendering differend to the older Standard version. If you open those two .img files from the same .mp in notepad, then you can see differenc in them. Not that I would understand what the differenz means, but there is one. I sure would like to find the problem, because the old version don't make G2 charts.