The 'printer driver' is a piece of software the printer manufacturer provides. Basically, it intercepts information directed to the printer and translates it into language the printer can understand. Any print jobs; from a web browser, email account, word processor, etc. are routed through the printer driver. Without a correctly installed driver, a printer will not print correctly.
We often receive calls from customers reporting an error like this. When the computer cannot communicate with the printer there are several possible causes. If you see an error like this on your computer screen, more often than not, it means the printer has 'raised a flag' telling the computer that there's a problem...
A common cause of communications errors between your computer and printer is cabling. Many devices like Tape drives, Zip drives, Scanners, etc. now make use of the printer port to save money. By using the printer port, you don't have to purchase a separate SCSI (or other) adapter and tear your computer apart to install it.