It's finally time for views_union to have an official release. People were having problems running views_union because it was based on an early, non-stable api for views 1.6. Now, it's been updated to the stable views api, and should work.
After months of neglect, this release now works. It was created with a views 1.6 RC, when the API was not stable. Therefore, it was a disappointment to people who used the stable views 1.6.
Now, it's been updated to the stable api, so it should work.