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.

‘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:

‘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.