acts_as_taggable_on environment issues

Like most people, I've got two machines: one for development and one
for production. I've done everything I can to make sure the ruby/rails
environments are the same, but of course they're not identical (I'll
get into that in a moment). The error that I'm getting happens when I
call a method in a background task controller on the production
machine; I have tried running the command on the production instance
itself as well as a development instance checked out from source
control (so running in the development Rails environment, but on the
production box). Here's what I'm seeing:

whisper:tidbitz mark$ ./script/runner
BackgroundController.sendEmailNotifications
/Users/mark/Documents/Feedback Games/development/tidbitz/vendor/rails/
railties/lib/commands/runner.rb:47: /Users/mark/Documents/Feedback
Games/development/tidbitz/vendor/rails/activerecord/lib/active_record/
base.rb:1667:in `method_missing_without_paginate': undefined method
`acts_as_taggable_on' for #<Class:0x20e1f08> (NoMethodError)
  from /Library/Ruby/Gems/1.8/gems/mislav-will_paginate-2.3.4/lib/
will_paginate/finder.rb:164:in `method_missing'
  from /Users/mark/Documents/Feedback Games/development/tidbitz/app/
models/tidbit.rb:3
  from /Users/mark/Documents/Feedback Games/development/tidbitz/vendor/
rails/activerecord/lib/../../activesupport/lib/active_support/
dependencies.rb:215:in `load_without_new_constant_marking'
  from /Users/mark/Documents/Feedback Games/development/tidbitz/vendor/
rails/activerecord/lib/../../activesupport/lib/active_support/
dependencies.rb:215:in `load_file'
  from /Users/mark/Documents/Feedback Games/development/tidbitz/vendor/
rails/activerecord/lib/../../activesupport/lib/active_support/
dependencies.rb:354:in `new_constants_in'
  from /Users/mark/Documents/Feedback Games/development/tidbitz/vendor/
rails/activerecord/lib/../../activesupport/lib/active_support/
dependencies.rb:214:in `load_file'
  from /Users/mark/Documents/Feedback Games/development/tidbitz/vendor/
rails/activerecord/lib/../../activesupport/lib/active_support/
dependencies.rb:95:in `require_or_load'
  from /Users/mark/Documents/Feedback Games/development/tidbitz/vendor/
rails/activerecord/lib/../../activesupport/lib/active_support/
dependencies.rb:260:in `load_missing_constant'
   ... 21 levels...
  from ./script/runner:3:in `eval'
  from /Users/mark/Documents/Feedback Games/development/tidbitz/vendor/
rails/railties/lib/commands/runner.rb:47
  from ./script/runner:3:in `require'
  from ./script/runner:3

Here are the things that I know are the same on both machines:
- Rails has been frozen in vendor/ at version 2.1.0
- In vendor/plugins I have two plugins, facebooker and mysql_bigint
- I've got the following gems in vendor/gems: mbleigh-acts-as-taggable-
on-1.0.2 and mislav-will_paginate-2.3.4
- Both machines have RubyGems 1.3.0
- Both machines are running MacOS X 10.5.5 with the latest security
updates.

Here are the things I know are different on the machines:
- Hardware
    - production: mac mini, dual core Intel
    - development: macbook pro, dual core Intel

- Ruby 1.8.6 patch level:
    - production: ruby 1.8.6 (2008-03-03 patchlevel 114) [universal-
darwin9.0]
    - development: ruby 1.8.6 (2007-09-24 patchlevel 111) [i686-
darwin9.0.0]

- Installed Gems

===== Production Gems installed ======
whisper:tidbitz mark$ gem list --local

*** LOCAL GEMS ***

actionmailer (2.1.1, 2.1.0, 2.0.2, 1.3.6, 1.3.3)
actionpack (2.1.1, 2.1.0, 2.0.2, 1.13.6, 1.13.3)
actionwebservice (1.2.6, 1.2.3)
activerecord (2.1.1, 2.1.0, 2.0.2, 1.15.6, 1.15.3)
activeresource (2.1.1, 2.1.0, 2.0.2)
activesupport (2.1.1, 2.1.0, 2.0.2, 1.4.4, 1.4.2)
acts_as_ferret (0.4.3, 0.4.1)
capistrano (2.5.0, 2.1.0, 2.0.0)
cgi_multipart_eof_fix (2.5.0, 2.2)
daemons (1.0.10, 1.0.9, 1.0.7)
dnssd (0.7.0, 0.6.0)
fastthread (1.0.1, 1.0)
fcgi (0.8.7)
ferret (0.11.6, 0.11.4)
gem_plugin (0.2.3, 0.2.2)
highline (1.4.0, 1.2.9)
hpricot (0.6.161, 0.6)
libxml-ruby (0.8.3, 0.5.2.0, 0.3.8.4)
mbleigh-acts-as-taggable-on (1.0.2)
mislav-will_paginate (2.3.4)
mongrel (1.1.5, 1.1.4, 1.1.3, 1.0.1)
mongrel_cluster (1.0.5)
needle (1.3.0)
net-sftp (2.0.1, 1.1.0)
net-ssh (2.0.4, 1.1.2)
rails (2.1.1, 2.1.0, 2.0.2, 1.2.6, 1.2.3)
rake (0.8.2, 0.8.1, 0.7.3)
RedCloth (4.0.3, 3.0.4)
ruby-openid (2.1.2, 2.0.3, 1.1.4)
ruby-yadis (0.3.4)
rubygems-update (1.3.0)
rubynode (0.1.5, 0.1.4, 0.1.3)
sources (0.0.1)
sqlite3-ruby (1.2.4, 1.2.1)
termios (0.9.4)

===== Development Gems installed ======
Luna:tidbitz mark$ gem list --local

*** LOCAL GEMS ***

actionmailer (2.1.1, 2.1.0, 2.0.2, 1.3.5)
actionpack (2.1.1, 2.1.0, 2.0.2, 1.13.6, 1.13.5)
actionwebservice (1.2.6, 1.2.5)
activerecord (2.1.1, 2.1.0, 2.0.2, 1.15.6, 1.15.5)
activeresource (2.1.1, 2.1.0, 2.0.2)
activesupport (2.1.1, 2.1.0, 2.0.2, 1.4.4)
acts_as_ferret (0.4.3, 0.4.1)
capistrano (2.5.0, 2.4.3, 2.1.0)
cgi_multipart_eof_fix (2.5.0)
columnize (0.1)
daemons (1.0.10, 1.0.8)
dnssd (0.7.0, 0.6.0)
facebooker (0.9.5)
fastthread (1.0.1)
fcgi (0.8.7)
ferret (0.11.6, 0.11.4)
flexmock (0.8.3)
gem_plugin (0.2.3)
highline (1.4.0)
hoe (1.7.0, 1.3.0)
hpricot (0.6.161, 0.6)
httpclient (2.1.2)
json (1.1.3, 1.1.2)
libxml-ruby (0.8.3, 0.7.0, 0.5.2.0)
linecache (0.43)
macaddr (1.0.0)
mbleigh-acts-as-taggable-on (1.0.2)
mislav-will_paginate (2.3.4, 2.3.3)
mongrel (1.1.5, 1.0.4)
mysql (2.7)
needle (1.3.0)
net-scp (1.0.1)
net-sftp (2.0.1, 1.1.0)
net-ssh (2.0.4, 2.0.3, 1.1.2)
net-ssh-gateway (1.0.0)
rails (2.1.1, 2.1.0, 2.0.2, 1.2.5)
rake (0.8.2, 0.8.1, 0.7.3)
RedCloth (4.0.3, 3.0.4)
ruby-debug (0.10.2, 0.10.0)
ruby-debug-base (0.10.2, 0.10.0)
ruby-openid (2.1.2, 1.1.4)
ruby-yadis (0.3.4)
rubyforge (1.0.0, 0.4.4)
rubygems-update (1.3.0, 1.2.0)
rubynode (0.1.5, 0.1.3)
soap4r (1.5.8)
sources (0.0.1)
sqlite3-ruby (1.2.4, 1.2.1)
termios (0.9.4)
uuid (2.0.1, 1.0.4)
ZenTest (3.10.0, 3.6.1)

That's all the differences I'm aware of. I have no idea what the
conflict is here, but if anyone can suggest another place to look for
Things That I Can Change, please let me know. If anyone's had (and
fixed) this issue before I'd love to know how!

Thank you!

Mark

After two days of installing, reinstalling, updating, downgrading,
wailing, gnashing of teeth, and a heavy dose of wine, the cause of the
problem, and probably the only meaningful difference between the two
computers initially, was this line in the development computers /etc/
profile:

export RUBYOPT=rubygems

That's it.

In the process of tracking this down, I updated to the latest patch of
ruby 1.8.6 (287) on both machines, and installed ruby in /usr/local on
the production box (rather than using the Apple provided version as I
had been doing). But Ruby versions, Gem versions, gems installed...
none of it mattered. That line was the only thing missing.

Mark