Mongrel gem install error .. how to

I am trying to set-up mongrel in osx but…

london:~ ab$ sudo gem install mongrel
Password:
Need to update 8 gems from http://gems.rubyforge.org

complete
Select which gem to install for your platform (powerpc-darwin8.8.0)

  1. mongrel 1.0.1 (mswin32)
  2. mongrel 1.0.1 (ruby)
  3. mongrel 1.0 (mswin32)
  4. mongrel 1.0 (ruby)
  5. Skip this gem
  6. Cancel installation

2
Install required dependency gem_plugin? [Yn] Y
ERROR: While executing gem … (TypeError)
can’t convert Hash into String

What am i doing wrong? All gems are at their latest version and in mint
condition…

Any help…