Hi cpuin,
This type of error is thrown when some widget is attached to DOM element, but the element with such ID or Class is missing.
From the attached parts of your code until now, is no visible the reason about this error.
The “.printButtons” class, mentioned in the error body, is not in your presented code.
Best Regards,
Ivailo Ivanov
jQWidgets Team
http://www.jqwidgets.com