OK, So I've made it work... for me. What I needed it for was to do quotes fro Regions, groups of countries, and apply a flat-rate price between certain weight brackets. So it does this now. I cleaned up the code a little, added some per-request caching to speed it up a little and reduce SQL query's.

I removed all the code that related to "over a certain weight charge nothing", which it does if as it returns zero if the weight doesn't fall between any rules weight bracket (so don't leave holes between rules).

The multi-page form still doesn't work for me and I entered all the data via phpMyAdmin directly into the table as I didn't have so many rules and I once spent 3 days trying to figure out how Drupals multi-page form works and am still none the wiser.

Also gave it a version number.

Hope this helps further the cause people.

Enjoy

p.s. No support for this I'm afraid. Its not my module