Invalid .gemspec format - multiple gem repos?

kristian-mandrups-macbook-pro:edgier kristianconsult$ rake db:migrate
(in /Users/kristianconsult/my_rails/rails3_apps/edgier)
WARNING: #<NoMethodError: undefined method `>’ for nil:NilClass>

-- encoding: utf-8 --

Gem::Specification.new do |s|
s.name = %q{abstract}

WARNING: Invalid .gemspec format in ‘/usr/local/Cellar/ruby/1.9.1-
p378/lib/ruby/gems/1.9.1/specifications/abstract-1.0.0.gemspec’
WARNING: #<NoMethodError: undefined method `>’ for nil:NilClass>

-- encoding: utf-8 --

Gem::Specification.new do |s|
s.name = %q{actionmailer}

WARNING: Invalid .gemspec format in ‘/Users/kristianconsult/.gem/ruby/
1.9.1/specifications/ZenTest-4.2.1.gemspec’
rake aborted!
no such file to load – test-unit
/Users/kristianconsult/my_rails/rails3_apps/edgier/Rakefile:4:in
`require’

I get a ton of these from all my installed gems it seems. Is it a
problem with my rails installation or should I clean my gems repo for
1.9.1 and start from fresh, or what could it be?
I have installed ruby using Homebrew. Seems like it looks for gems in
two different locations!?

I am using a rails 3 app which should work as is, since I got it from
someone else:

“You can get my bundle packed version of this app, complete with an
undeveloped cucumber feature from
http://www.nuclearfuzzgrunge.com/images/edgier.tar.bz2

Found the bug and solution here:

https://rails.lighthouseapp.com/projects/8994/tickets/3865-invalid-gemspec-format-in-and-already-initialized-constant-warnings-with-ruby-192dev