Unable to install properly / use acts_as_taggable_on -- please help

The gem (now installed as a plugin) puts into the log the default text that it was loaded successfully, but for 'acts_as_tagger' and 'acts_as_taggable_on' -- I get NoMethodError for these. Also, rake spec:plugins fails with two errors.

1) 'Taggable should be able to get tag counts on an association' FAILED expected: 2,      got: 1 (using ==) ./vendor/plugins/acts-as-taggable-on/spec/acts_as_taggable_on/ taggable_spec.rb:88:

2) 'Taggable should be able to use named scopes to chain tag finds' FAILED expected: [#<TaggableModel id: 35, name: "Bob", type: nil>],      got: (using ==) ./vendor/plugins/acts-as-taggable-on/spec/acts_as_taggable_on/ taggable_spec.rb:117:

I've run the migration as indicated, and restarted the server, all in various permutations, and I still get errors.

specifically I am trying to use it as such

class User   acts_as_tagger end

class Group   acts_as_taggable_on :interest end

My app only works with those lines commented out. Any help is greatly appreciated. Thanks in advance.