Kevin Marsh

If you encounter this issue booting up a Mongrel:

$ ./script/server 
/Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `gem_original_require': no such file to load -- builder/blankslate (LoadError)
from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `require'
from /Users/kmarsh/Sites/sampleboardportal/vendor/rails/activesupport/lib/active_support/basic_object.rb:3
from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `gem_original_require'
from /Library/Ruby/Site/1.8/rubygems/custom_require.rb:27:in `require'
from /Users/kmarsh/Sites/sampleboardportal/vendor/rails/activesupport/lib/active_support.rb:29
from /Users/kmarsh/Sites/sampleboardportal/vendor/rails/railties/lib/commands/server.rb:1:in `require'
from /Users/kmarsh/Sites/sampleboardportal/vendor/rails/railties/lib/commands/server.rb:1
from ./script/server:3:in `require'
from ./script/server:3

…it’s because you’re missing Builder. Try sudo gem install builder. Fixed the issue for me!