iBook freezes when items are sent to print

hi there.

our iBook freezes whenever we send something to print. the icon for the printer never shows up in the icon bar and there is no reaction from the printer, but when the computer is restarted, the printer spits out whatever was being printed.

this happens no matter how many applications are open, and even when the printer's usb cable is plugged directly into the computer (our normal set-up has the printer's usb plugged into a usb hub that houses a couple other peripherals.)

any ideas?