Installation of Nagios on Fedora 15 is easy as yum install nagios nagios-plugins* php nrpe. I only found one problem: Error: Could not read object configuration data!
The webserver runs as user apache, which cannot access /etc/nagios/objects by default. Chmod or chown the directory to fix it, or add user apache to the group nagios.
You may also want to check the selinux settings, which can be restored by typing restorecon /etc/nagios© GeekLabInfo Fedora 15: Nagios errors is a post from GeekLab.info. You are free to copy materials from GeekLab.info, but you are required to link back to http://www.geeklab.info