I was having problems just entering a value in the regions. I looked at the code and the form seemed to be a 'multistep' form but there was only one step. Drupals handling of multi-step forms is ... problematic as I found out doing the 'uc_import_csv' module so changed it to a simple form, added a TAPIr table and some other little bits and pieces. My version is attached. Perhaps you can merge with the main version if you like it.

Also, the uc_regions table is a bit ugly in that the 'countries' column should be replaced with its own table which would just be a join between the 'uc_countires' table and the 'uc_regions' table.

This module needs some cleaning up database wise. I hope my changes are a step in the right direction.