Printing dimensions in Illustrator CS2


I'm having problems setting a size for print out. I've done the following in illustrator:

artboard size
W: 15.4 cm
H: 21.6 cm

When I print it out each measurement is out by a few millimetres. I've checked all my print settings to make sure its not scaling or that there are hidden margins. Still having the same problems??? Has anyone else had this?