when i try and run the "rails server" or "rake jobs:work" i get the error: "no such file to load -- treetop/runtime"

full trace:

macbook-pro-2:domain ryan$ rake jobs:work --trace(in /Applications/htdocs/domain) rake aborted! no such file to load -- treetop/runtime /opt/local/lib/ruby/gems/1.8/gems/mail-2.2.14/lib/mail.rb:68:in require' /opt/local/lib/ruby/gems/1.8/gems/mail-2.2.14/lib/mail.rb:68 /opt/local/lib/ruby/gems/1.8/gems/mail-2.2.14/lib/mail.rb:61:ineach' /opt/local/lib/ruby/gems/1.8/gems/mail-2.2.14/lib/mail.rb:61 /opt/local/lib/ruby/gems/1.8/gems/delayed_job-2.1.2/lib/delayed/performable_mailer.rb:1:in require' /opt/local/lib/ruby/gems/1.8/gems/delayed_job-2.1.2/lib/delayed/performable_mailer.rb:1 /opt/local/lib/ruby/gems/1.8/gems/delayed_job-2.1.2/lib/delayed_job.rb:5:inrequire' /opt/local/lib/ruby/gems/1.8/gems/delayed_job-2.1.2/lib/delayed_job.rb:5 /opt/local/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:in require' /opt/local/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:64:inrequire' /opt/local/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:in each' /opt/local/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:62:inrequire' /opt/local/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:in each' /opt/local/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler/runtime.rb:51:inrequire' /opt/local/lib/ruby/gems/1.8/gems/bundler-1.0.7/lib/bundler.rb:112:in require' /ApApplications/htdocs/domain/config/application.rb:7 /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:ingem_original_require' /opt/local/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in require' /Applications/htdocs/domain/Rakefile:4 /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2383:inload' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2383:in raw_load_rakefile' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2017:inload_rakefile' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in standard_exception_handling' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2016:inload_rakefile' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2000:in run' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:instandard_exception_handling' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in run' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 /opt/local/bin/rake:19:inload' /opt/local/bin/rake:19

in my Gemfile i have: "gem 'delayed_job'"