I'm having this issue and it does not seem to necessarily be jQuery related... at least I have tried installing the jQuery Update official release:

http://ftp.drupal.org/files/projects/jquery_update-6.x-1.1.tar.gz

...And the development snapshot:

http://ftp.drupal.org/files/projects/jquery_update-6.x-2.x-dev.tar.gz

...neither seems to resolve the issue.

dwkitchen, what specific steps did you take to resolve this issue?

Another user is having the same problems, see this message board posting:

http://www.ubercart.org/forum/support/11341/flat_rate_shipping