I am using composer (http://getcomposer.org/) to manage installed bundles in the Symfony2 (symfony v 2.1.3). Version of the composer is de3188c.
Symfony2
de3188c
In my case, the above suggestions didn't make a difference. What did was to use the HTTPS protocol for packagist:
HTTPS
packagist
php composer.phar config --global repo.packagist composer https://packagist.org
or
composer config --global repo.packagist composer https://packagist.org
depending on your setup