(At least on Leopard with Ruby 1.8.6)

Ruby will try to reload rmagick if you get the case of rmagick different from the original require. And when that happens it all goes up the whop.

We were using attachment_fu’s image magick processor, then doing a require ‘rmagick’ seperately which resulted in tonnes of errors like this

/usr/local/lib/ruby/gems/1.8/gems/rmagick-1.15.10/lib/rmagick.rb:32:
  warning: already initialized constant PercentGeometry

Keep your case’s of require’s consistent. Even if this is file system dependent behaviour in mixed development environments you can imagine how weird problems could get!