When printing from Illustrator CS3 in Mac OS X 10.4 the progress bar showing print progress will hang halfway through the job will print successfully from the printer but Illustrator requires a force quit.
Hide the Dock. You can test this by watching the print queue icon bounce into the Dock at the same time the stall happens.
Pulled this fix from the Adobe Forums. Usually document specific and it does not appear to happen in 10.5.