betternestedset outside of rails


I've been putting together database scripts that rely on Active Record outside of rails - this link was very helpful in getting started:

Now though, I'm having a problem getting this to work with betternestedset.

Can anyone tell me how to require these nested methods in an external script? These don't seem to pick them up:

require 'rubygems' require 'active_record'

My error is:

C:/MyDevelopment/InstantRails/ruby/lib/ruby/gems/1.8/gems/ activerecord-1.15.3/lib/active_record/base.rb:1860:in `method_missing': undefined method `move_to_child_of' for #<Employeetree:0x9466a28> (NoMethodError)

thanks! Andrew