Instructions for clearing print jobs from the queue:

Pause the print queue:
In the print queue screen click Printer in the menu bar.
Click Pause Printing (a checkmark will appear before Pause Printing).

Cancel a single print job (usually the top print document) in the queue:
Highlight the top print job in the list.
Click Document, then Cancel (this cancels only the one highlighted document).
If you cannot get the top print job to disappear, you may have to recycle
the printer once or twice to clear the memory of the printer completely.  To
Recycle the
printer, turn off the power, wait 30 seconds and plug it back in.

OR:
Purge all print jobs in the queue: (requires special privileges)
Click Printer, then Purge Print Documents.
The entire list of print jobs should disappear.

Unpause (restart) the print queue:
(Remember to unpause the queue or the job won't print!!)
Click Printer, then Pause Printing (checkmark now disappears from Pause
Printing option)
Exit print queue screen.

Try printing a second time.