Please upgrade to 2.2 here.
The 2.0 and 2.1 branches are no longer being updated.
Registration Broken / Birthday Year
It seems that the latest version of Vanilla has introduced a bug that results in the year not being listed on the registation forum. Because it isn't listed, it means that no new user can register. Take a look at the registration form here:http://forum.wbpsystems.com/entry/