Passenger won't allow ActiveRecord to be extended?

After much tinkering, I have discovered that any module or plugin which
extends ActiveRecord causes Passenger to fail (application won’t load at
all).

Is this a known behavior?

I have confirmed that my Passenger installation is working just fine
with a simple Rails application that does not modify AR.

Passenger 2.0.3
OS X 10.5.4
Built-in Apache 2.2
ruby 1.8.6(114)
Rails 1.2.6

In one case, I’m doing this:

module ActiveRecord
module Validations
module ClassMethods
# adding my custom methods here
end
end
end

And in another, I have created an acts_as plugin which is loaded by
conventional means of:

ActiveRecord::Base.send(:include, GW::ActsAsPessimistic)

This seems to be prettty sttandard stuff, and it works just fine on
several dev boxes using mongrel, so I don’t see how I’m supposed to do
anything different in my source code.

(admittedly cross posted from Passenger user list to cast broader net on
this one because it’s Saturday, and I’d really like to solve it before
Monday)

– gw