Why doesn't the Exit button in my course work?

This is an area where the courseware standards (SCORM, AICC) don't really correspond with real-world usage.

According to SCORM, exiting a course is considered a navigation event and so should not be invoked by the course itself—only the run-time environment (typically LMS) is supposed to control navigation. This is related to the SCORM philosophy of "reusable objects"—if an content object (SCO) contains a button that closes the window then it's making strong assumptions about where it will run (i.e. in a separate window rather than as part of a larger course) and hence is less reusable. So if one were to follow SCORM to the letter then the course should not have an Exit button at all.

In reality almost nobody does it that way—having an Exit button is a very common requirement.

EKP typically launches courses inside a frameset—frames are used for navigation, and a "hidden" frame is used for the SCORM API adapter. That's why window.close() won't work—it tries to close the frame rather than the top level window. If you use window.top.close() instead it should work in EKP. (Note: the name of the window object in JavaScript might be misleading, as it can refer to either a frame or a top-level window.) But there's no single method that's guaranteed to be 100% portable across LMSs, even if they are SCORM- and/or AICC-conformant.