This module has not been updated for the USPS January 22, 2012 changes ...

There is a RateV3 that is updated for the USPS January 22, 2012 changes in the Free Software Add Ons ...

Until this contribution is updated, you will probably need to go to the USPS January 22, 2012 for RateV3 if you want the First Class International to work ...

You might look at the Announcements on this, if you have trouble finding it:
http://www.zen-cart.com/forum/showthread.php?t=191406