[Nagiosplug-help] check_nagios not finding nagios process

[Michael Shoemaker]

# /usr/local/nagios/libexec/check_nagios -e 
10 -F /usr/local/nagios/var/status.dat -C /usr/local/nagios/bin/nagios

NAGIOS CRITICAL: Could not locate a running Nagios process!


however:

# ps -ef | grep nagios
  nagios 18012     1  0   Jun 23 ?        
2:32 /usr/local/nagios/bin/nagios -d /usr/local/nagios/etc/nagios.cfg


am I missing something on the syntax?