This here is a different issue, as you've edited the query and now have an extra comma in it:

[...],ClassSchedule.EventDate) AS Until,, [...]
                                      ^^^^
[download]

If it still doesn't work after correcting this, you might also try to increase the debug level; make it 2, then 3, 4, ...
Might be that that would show more to get a clou about what's wrong.