What kind of printer do you have? And when you say you can't print multiple copies, is the problem that you can't set the number of copies in the print dialogue box, or is it that you only get one copy printed even though you were able to set the number of copies to (for example) 2?
Some printers can print multiple copies on their own - for these Windows sends only 1 copy to the printer along with instructions to "print twice". This is known as "mopier mode". If Windows thinks your printer can do this but it really can't, then it could explain why you're having the problem. Try checking the setting for your printer:
Start -> Devices and Printers
Right-click the printer and select "Printer Properties" (NOTE - not just "properties")
Click the "Device Settings" tab
The "Mopier Mode" setting is under "Installable Options"