jQuery.form.js from jQuery Update kills the ahah process when upload module enabled

I'm writing a cck module to replace my old D5 version of cck_address. There is good reason why I'm not just using the addresses module, but that is neither here nor there.

I have my module working flawlessly using core, cck 3.0 alpha 1, ahah_helper 2.x (plus some patches), and that's it. I can also enable EITHER the core upload module, OR the latest jQuery Update module, but not both. I have isolated which file blows things up by commenting out the lines from jQuery Update which specify the files to override one at a time. The file in question is jquery.form.js. If I copy the core file to the update location, then everything works, so that is a double-check that it IS that file.

So does anyone have a clue what in upload and jquery.form.js would jack with an ahah_helper replacement cycle? Specifically, in my module, I'm referring to selecting a new country from a drop down which replaces all fields for that address and updates the options for the state/province field.

I'm attaching the module and my version of ahah_helper in case you want to duplicate the issue.

I think the version of CCK doesn't matter. I think the version of jQuery Update doesn't matter so long as it's recent.

Steps to take:
1) copy all modules but don't install/activate 'upload' or jquery_update yet
2) create a content type called 'test'
3) create a field using the cck_address module (attached) - settings shouldn't matter - remember to go to the cck_address settings first and activate at least 2 countries; you'll get a message when you install to do so (I activated the U.S. and the UK)
4) create that content type and the UK should be the default, so change the country to the US. note that this works!
5) activate either the upload module, or the jquery module, but not both
6) edit or create another 'test' node and note that it still works
7) activate the other module
8) edit or create another 'test' node and note that it NO LONGER WORKS - oh, no!
9) go into the node settings and set attachments to 'disabled'
10) edit or create another 'test' node and note that it works again
11) re-enable attachments for that node type
12) replace the jquery.form.js file found in the jquery_update module with the one in core
13) edit or create another 'test' node and note that it still works

So I'm thinking that something in upload is calling something in jquery.form.js and interfering, but I haven't any clue how to proceed in testing.

Unfortunately, the version of jquery.form.js that is in core is compressed, so doing a diff of the old and new version is meaningless. Plus, the old version isn't found in the repository for the jquery.form.js plugin itself. The author only has copies going back to 2009.

I know there are jQuery geniuses out there. Help!