Install Symfony Plugin: Warning: require_once(PEAR.php): failed to open stream

1. If you try to install a plugin (ex. prestaPaypalPlugin) with symfony cli and get something like this...
   sakra:/var/www/sakra# ./symfony plugin:install prestaPaypalPlugin
   >> plugin    installing plugin "prestaPaypalPlugin"
   Warning: require_once(PEAR.php): failed to open stream: No such file or directory in mnt/vol1/vol1/www/sakra/lib/vendor/symfony/lib/plugin/sfPearEnvironment.class.php on line 15
   Fatal error: require_once(): Failed opening required 'PEAR.php' (include_path='.:/usr/share/php:/usr/share/pear') in /mnt/vol1/vol1/www/sakra/lib/vendor/symfony/lib/plugin/sfPearEnvironment.class.php on line 15
2. Run: apt-get update
3. Run: apt-get install php-pear
4. Run again: ./symfony plugin:install prestaPaypalPlugin
5. If you get an error like this...
   No release available for plugin "prestaPaypalPlugin" in state "stable"
6. Run with -s parameter (to enable beta plugins): ./symfony plugin:install -s beta prestaPaypalPlugin