So I finally gave in, and in wp-contact-form-7.php
I set the WPCF7_LOAD_JS to false.
The form works now, BUT... from the user's standpoint, exclusive checkboxes no longer act as exclusive (it does only send me one response, but the form seems to choose which response it will send to me), and I'm sure other js goodies are missing.
As peterhol says, it's very distressing to be without the js when they're part of what makes the plugin so good!
Since everybody seems to have looked for plugin conflicts in this thread and we aren't having any, any possibility this is a WP issue? I'm using 2.9.2. Searched around the forums to see if there are any reports of strangeness with js and 2.9.2 but I don't see any.
I really want to get this fixed the right way and I don't want to give up on CF7 to do it.