Currently the software supports US-domiciled carriers; we don't have a few fields needed by Canada yet. The Canadian rules are in there for drivers that cross into Canada, but the form just isn't Canada-approved.
If you still want to try it, I suppose you could use your US-domiciled carrier's address, or register but use the closest US State to your province; just realize we won't be able to mail anything to you, so be sure to use a valid email address.
Hope that helps...
--LarryBoy