I installed Nagios today but for some reason it doesn't wanna work... I installed on RedHat 9.0, the service start just fine:
nagios 2642 0.0 0.1 10300 1012 pts/1 S 22:32 0:00 /usr/local/nagios/bin/nagios nagios.cfg
nagios 2767 0.0 0.1 3568 624 pts/0 S 22:46 0:00 grep nagios
I verfied the Log and this is what I have in my log:
 Nagios 2.0 starting... (PID=2642)
 LOG VERSION: 2.0
I'm not using mySQL, everything is text file.... we I login to Nagios page, I'm getting the following error:
Error: Could not read host and service status information!
The most common cause of this error message (especially for new users), is the fact that Nagios is not actually running. If Nagios is indeed not running, this is a normal error message. It simply indicates that the CGIs could not obtain the current status of hosts and services that are being monitored. If you've just installed things, make sure you read the documentation on starting Nagios.
Some other things you should check in order to resolve this error include: .....