dev_appserver.rb cannot start after rubygems update on Ubuntu 10.04

I had rubygems 1.3.5 (or 1.3.6?) installed and then made a sudo gem update after a long while again. Some gems complained they needed a newer gems version. Because sudo gem update --system is deactivated on Ubuntu I followed these steps: How can I get RubyGems 1.3.6 on Ubuntu 10.4 But now I cannot start the dev_appserver.rb anymore, it says:

=> Bundling gems
ERROR:  While executing gem ... (Runtim开发者_StackOverflow中文版eError)
    Unknown command bundle

I also tried to do sudo gem update and sudo gem update --system again a few times but everything is up-to-date now. Here is a list of my gems: http://pastebin.com/cFaTCyF5

It's a bit of a hack around but I can't really tell what's going on properly from what you sent but I know a few people have been having problems after running gem update --system lately. Find out what version you've just installed with

gem list

Look for the update, should look something like this: rubygems-update-1.5.0

Then try rolling back your rubygems version

sudo gem uninstall rubygems-update -v 1.5.0
sudo gem install rubygems-update -v 1.4.2          <-- try a different version

gem install --system 1.3.7 worked in my case