This is 5 years later, but I stumbled across this question while having this same error in the console during a setup of the jQWidgets library. This error likely means that the project or application you are using depends on jQWidgets and either does not have jQuery included before the library is used (jQWidgets depends on jQuery as the name suggests), or is missing the core reference to the library before it is used. For me making sure to include a reference to jqxcore.js before attempting to use a widget fixed it.
See this forum thread from the jQWidgets website for more information: https://www.jqwidgets.com/community/topic/uncaught-referenceerror-jqxbaseframework-is-not-defined/
Here is a link to the jQWidgets documentation as well: