Earned XP not being added to student total

I'm having a problem with XP not being awarded to a particular student in my course. I've created a normal quest, signed in as the student and submitted it. Signed back in as myself and approved it, and.... his total XP doesn't budge. Here is a video description http://screencast.com/t/Mw0nwZIKZTy. Any help would be appreciated because this will cause a significant difficulty in my moving forward!
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