Are they not shown at all in Sheetcam? Or just not recognized as a drill operation? I've found they have to import as actual circles to be recognized for a drill operation. If you convert them to curves (or something like that) in your drawing, they may not register as circles when imported into Sheetcam.
Sorry, that's the only thing I could see that would cause the points not to be recognized. Check to see that the layer the points are on is not "frozen". I am not sure if that would make a difference or not, but worth a shot.