Well, if you play the special features of the DVD menu about Egyptology and read the page for the Canopic Jars, it explains that in the ancient Egypt they used to put the most important organs of the body to be embalmed in FOUR canopic jars. Now play the movie and at 4min 25sec you will see that during the ceremony there are FIVE jars aligned on the altar.
Didn't they read anything before writing the screenplay?