We've been having the same error showing up in large numbers, on our big 9040 and 9050 printers in our open access labs.
Our testing narrowed it down to the same thing contributor "Imagenet_Tech" posted above - offending web pages.
Early on we eliminated the print servers (by printing straight to the printers via IP printing).
We've also eliminated the browsers themselves (IE, Firefox, Chrome, etc.), as they all caused the same 49.4c02 error, when attempting to print certain web pages.
Again as "Imagenet_Tech" listed, we're looking into offending components, within these web pages (scripts, certain html code, web server versions these pages are using, etc.)
Definitely puzzling........