I have got Adobe Illustrator CS3 on my iMac, Mac OS X 10.7 Lion. I recently got a new printer, an HP Photosmart B110, product number CN245B, serial number CN1393K1Q405J8, driver version HP Inkjet 8 Driver 3.5.2. For some reason, whenever I press Print in the File menu in Illustrator it crashes, taking my work along with it. So I have to save it and open it with Preview and print it from there. But the colours change. For example, this image:

looks like this after it has been printed (a scan):

The two a letters are done with a linear gradient with no blending, but it's exactly the same colour.
It does work if I export the ai as a png/jpeg in preview.
What do I do?