Div is used in PostScript to perform a division. If you send the following code: 12 2 div == to a PostScript RIP, it will reply with 6.
The PostScript error ‘typecheck’, offending command: ‘div’ is typically associated with printing Illustrator 7.0 EPS files from PageMaker or other applications. If you are using such EPS files, please save them in Illustrator 6.0 EPS format. As far as I know this error has been fixed in Illustrator 7.02.
A div error caused of a divide by zero can also occur when printing from a Mac PowerPoint file containing a two-color gradient background to a HP 4xxx printer. Replacing the background by a solid color resolves the issue.