Here's the answer:
FALL/WINTER 2011/12 Undergraduate REGISTRATION
The last day to add/drop Term 1 and Term 3 courses is September 16, 2011; and for Term 2 courses is January 11, 2012.
The last day for cancelling courses without academic penalty for Term 1 is November 11, 2011; and for Term 2 and 3 is March 9, 2012.
Hope this helps.