I have the same issue. I had two machines upgraded to rails 2.0.2 from 1.2.6. These are fine (one OS X and the other CentOS 5).
The new machine I just built, had this problem with acts_as_taggable. It clearly can work with 2.0.2 as it does on the other two machines. However, if you don't have the 1.2.6 or something installed, it will not work.
I tried to just install 1.2.6:
gem install rails --version=1.2.6
but no luck.
Then I tried to install 1.2.3:
gem install rails --version=1.2.3
still no luck.
Then gem update (to see if the upgrade helped it but no luck).
|