title: Unable to start the Phusion Passenger watchdog?
body: <p>I have done a Phusion Passenger setup on Ubuntu 10.04, with Apache2. Whenever I restart the Apache server I got the following error message, and the Rails application is not running.</p>
  
  <pre><code>[error] *** Passenger could not be initialized because of this error: Unable to start the Phusion Passenger watchdog because its executable (/usr/lib/phusion-passenger/agents/PassengerWatchdog) does not exist. This probably means that your Phusion Passenger installation is broken or incomplete, or that your 'PassengerRoot' directive is set to the wrong value. Please reinstall Phusion Passenger or fix your 'PassengerRoot' directive, whichever is applicable.
  </code></pre>