As you might imagine, uninstalls aren't something we get to test a whole lot. However, as you've been posting issues, they've been getting fixed in the code. You ought to use the latest versions available on clean installs, and while we'll put a beta 3 out in the near future, to avoid some difficulties you can try the download at http://bazaar.ubercart.org.

Perhaps the workflow-ng thing was causing the difficulties before w/ shipping? Who knows.. Sorry you've had such a rough go, but thanks for keeping us informed throughout the process. (And regarding those uninstall error messages, there's no way for us to trap every bad query and return a user friendly warning. Best thing to do is just post it up if you're worried about it and let us fix it in the code if need be. You can usually tell which module is giving you grief by looking at the table name.)