我正在尝试使用他们的指南启动Redmine，但最终无法使用Passenger 启动apache。错误日志：
[Thu Jun 06 19:56:01 2013] [notice] caught SIGTERM, shutting down
[Thu Jun 06 19:56:03 2013] [error] *** Passenger could not be initialized because of this error: Unable to start the Phusion Passenger watchdog because its executable (/usr/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.
[Thu Jun 06 19:56:03 2013] [error] *** Passenger could not be initialized because of this error: Unable to start the Phusion Passenger watchdog because its executable (/usr/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.
[Thu Jun 06 19:56:03 2013] [notice] Apache/2.2.22 (Debian) Phusion_Passenger/4.0.5 mod_ssl/2.2.22 OpenSSL/1.0.1e configured -- resuming normal operations
载客量
LoadModule passenger_module /usr/local/lib/ruby/gems/1.9.1/gems/passenger-4.0.5/libout/apache2/mod_passenger.so
PassengerRoot /usr/lib/phusion-passenger/
PassengerDefaultRuby /usr/local/bin/ruby/
PassengerDefaultUser www-data
和
# find / -name PassengerWatchdog
/usr/lib/phusion-passenger/agents/PassengerWatchdog
/usr/local/lib/ruby/gems/1.9.1/gems/passenger-4.0.5/agents/PassengerWatchdog
问题出在哪里？