Today i wanted to try the new ruby on rails v3. The standard way of installation:

gem install rails

on snow leopard simply died with the following error:

ERROR: While executing gem ... (ArgumentError)
string contains null byte

Turns out that somehow gem could not read the downloaded .tar files of the mail as well as activesupport gems. So the solution was rather simple i downloaded those thow from rubygems.org and installed them using:

gem install --local ~/Downloads/activesupport-3.0.0.gem
gem install --local ~/Downloads/mail-2.2.5.gem


There were only a few dependencies to satisfy, but all installed perfectly using standard gem.

After installing activesupport and mail locally, installing rails version 3 finished without a problem.