do you have minimal.cfg file instead?
if so, then configure the settings in this file (go to ww.nagiosbook.org and see there a "how to" install Nagios. There is a section dedicated about minimal.cfg file.)
After this, go to nagios.cfg and comment out all lines like cfg_file=/etc/nagios/*bla...bla..bla...*
and enter a new line which says cfg_file=/ **enter the minimal.cfg file pathe here ***
Thus, you are telling Nagios to use minimal.cfg instead of contacts.cfg and all the other .cfg files...
But if you don't have minmal.cfg installed either..I dunno..