[Rails] Uninitialized constant ApplicationController?

[David Mitchell]

Hello list,

I'm trying to start my Rails server after doing a long complex switch
from Postgres to MySQL, and I'm getting the following error:

=> Booting WEBrick...
/usr/lib/ruby/gems/1.8/gems/activesupport-1.2.5/lib/active_support/dependencies.rb:200:in
`const_missing': uninitialized constant ApplicationController
(NameError)
        from script/../config/../vendor/plugins/user_engine/lib/user_engine.rb:74:in
`included'
        from ./script/../config/../app/helpers/application_helper.rb:5
        from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:21:in
`require'
        from /usr/lib/ruby/gems/1.8/gems/activesupport-1.2.5/lib/active_support/dependencies.rb:214:in
`require'
        from script/../config/../vendor/plugins/bundled_resource-0.9/init.rb:18:in
`load_plugin'
        from /usr/lib/ruby/gems/1.8/gems/rails-1.0.0/lib/initializer.rb:311:in
`load_plugin'
        from /usr/lib/ruby/gems/1.8/gems/activesupport-1.2.5/lib/active_support/core_ext/kernel.rb:27:in
`silence_warnings'
        from /usr/lib/ruby/gems/1.8/gems/rails-1.0.0/lib/initializer.rb:311:in
`load_plugin'
         ... 10 levels...
        from /usr/lib/ruby/gems/1.8/gems/rails-1.0.0/lib/commands/server.rb:28


I've seen the 'Uninitialized constant ...' message before, but it's
always been because of a simple typo on my part, or a version mismatch
somewhere.  I'm on Gentoo Linux, MySQL 5.0.18, Rails 1.0, current
versions of login_engine and user_engine, and that combination of
versions seems to be fine as far as I can tell.

Any suggestions where to look?

Thanks in advance

Dave M.