TextMate bundle not using environment variable to find Ruby library

Something is going on in my TextMate bundle–it’s calling the wrong lib
for Ruby. I have the environment variables set like this:

TM_RSPEC_HOME /usr/local/lib/ruby/gems/1.8/gems/rspec-1.1.3
TM_RUBY /usr/local/bin/ruby

When I run these queries in a TextMate window I get this:

which ruby
/usr/local/bin/ruby
which rails
/usr/local/bin/rails

But still when I try to run a spec in TextMate, I get this:

/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in require' /Users/lisasawin/Library/Application Support/TextMate/Bundles/RSpec.tmbundle/Support/lib/spec/../spec/mate/runner.rb:14:inrun_file’ from /tmp/temp_textmate.zQ2Hv1:4

How can I get TextMate to use the library in usr/local/bin/ruby instead
of looking in usr/local/bin/ruby? Thanks so much for any help!

Lisa