duskstardust, thanks for posting that image, that was actually very helpful.
I removed it for now, just so others don't use the file to get a free pattern.
But it's pretty clear to me what's happening now. I notice the printed page is also lacking the grey fill that is supposed to be inside all the black outlines of the pattern.
So my guess is that your printer is somehow set to print black and white only... like literally, only the entirely black parts will print. Anything in a shade of grey is just not printing. This includes the pattern fill, the sample image in the corner, and the difficulty level that is printed in the corner. All are grey.
So I'd check your printer settings and see if you can tell it to print color, or greyscale. Something besides black line art. I'm hoping you can find an option for that.
Also, the print system doesn't use the Flash plugin any more, so that shouldn't be related to the problem.