invalid gemspec

Hi I ve updated my Ruby Version with sudo gem update rails
and afterwards sudo gem update --system

Now I want to start an new rails Application

rails OnTrack

and recieve

boris-brandens-macbook:rubycode borisbranden$ rails ontrack
Invalid gemspec in [/Library/Ruby/Gems/1.8/specifications/json-1.6.1.gemspec]: invalid date format in specification: "2011-09-18 00:00:00.000000000Z"
Invalid gemspec in [/Library/Ruby/Gems/1.8/specifications/tilt-1.3.3.gemspec]: invalid date format in specification: "2011-08-25 00:00:00.000000000Z"
/Library/Ruby/Site/1.8/rubygems/dependency.rb:247:in `to_specs': Could not find tilt (!= 1.3.0, ~> 1.1) amongst [RedCloth-4.1.1, abstract-1.0.0, actionmailer-3.1.1, actionmailer-3.0.1, actionmailer-2.3.9, actionmailer-2.3.8, actionmailer-2.3.5, actionmailer-1.3.6, actionpack-3.1.1, actionpack-3.0.1, actionpack-2.3.9, actionpack-2.3.8, actionpack-2.3.5, actionpack-1.13.6, actionwebservice-1.2.6, actionwebservice-1.2.6, activemodel-3.1.1, activemodel-3.0.1, activerecord-3.1.1, activerecord-3.0.1, activerecord-2.3.9, activerecord-2.3.8, activerecord-2.3.5, activerecord-1.15.6, activeresource-3.1.1, activeresource-3.0.1, activeresource-2.3.9, activeresource-2.3.8, activeresource-2.3.5, activesupport-3.1.1, activesupport-3.0.6, activesupport-3.0.1, activesupport-2.3.9, activesupport-2.3.8, activesupport-2.3.5, activesupport-1.4.4, acts_as_ferret-0.4.3, addressable-2.2.2, arel-2.2.1, arel-1.0.1, authlogic-2.1.6, aws-s3-0.6.2, builder-3.0.0, builder-2.1.2, bundler-1.0.3, capistrano-2.5.2, cgi_multipart_eof_fix-2.5.0, daemons-1.0.10, delayed_job-2.0.3, dnssd-0.6.0, erubis-2.7.0, erubis-2.6.6, fastthread-1.0.1, fcgi-0.8.7, ferret-0.11.6, gem_plugin-0.2.3, highline-1.5.0, hike-1.2.1, hpricot-0.6.164, http_accept_language-1.0.1, i18n-0.6.0, i18n-0.4.1, libxml-ruby-1.1.2, mail-2.3.0, mail-2.2.7, mime-types-1.16, mongrel-1.1.5, multi_json-1.0.3, mysql-2.8.1, needle-1.3.0, net-scp-1.0.1, net-sftp-2.0.1, net-sftp-1.1.1, net-ssh-2.0.4, net-ssh-1.1.4, net-ssh-gateway-1.0.0, paperclip-2.3.4, polyglot-0.3.1, rack-1.3.5, rack-1.2.1, rack-1.1.0, rack-1.0.1, rack-bug-0.3.0, rack-cache-1.1, rack-canonical-host-0.0.1, rack-mount-0.8.3, rack-mount-0.6.13, rack-ssl-1.3.2, rack-test-0.6.1, rack-test-0.5.6, rails-3.1.1, rails-2.3.9, rails-2.3.9, rails-2.3.8, rails-2.3.5, rails-1.2.6, railties-3.1.1, railties-3.0.1, rake-0.8.7, rake-0.8.3, rdoc-3.11, ruby-openid-2.1.2, ruby-yadis-0.3.4, rubygems-update-1.8.11, rubygems-update-1.3.7, rubynode-0.1.5, rvm-1.0.14, sprockets-2.0.3, sqlite3-ruby-1.2.4, termios-0.9.4, thor-0.14.6, thor-0.14.3, treetop-1.4.8, tzinfo-0.3.31, tzinfo-0.3.23, xml-simple-1.0.12, xmpp4r-0.4] (Gem::LoadError)

from /Library/Ruby/Site/1.8/rubygems/specification.rb:761:in `activate_dependencies'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:758:in `each'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:758:in `activate_dependencies'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:742:in `activate'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:764:in `activate_dependencies'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:758:in `each'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:758:in `activate_dependencies'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:742:in `activate'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:764:in `activate_dependencies'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:758:in `each'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:758:in `activate_dependencies'
from /Library/Ruby/Site/1.8/rubygems/specification.rb:742:in `activate'
from /Library/Ruby/Site/1.8/rubygems.rb:1211:in `gem'
from /usr/bin/rails:18

Any ideas what to do