This mod had been tested and works on all versions of zen (including 1.3.8a).
When you upgraded could you possibly have altered the way the "state" field displays on the "create an account" form?
Older versions had a bug in them when the state was selected from a drop down (instead of entered by hand into a text field.)
My new version (1.2.7) soon to be released should correct this issue.
How do you have customers enter their "state" on that form currently?
Bookmarks