The error is just as it's stated, you have no .cfg files.
When you install from source, all of the config files are there, but they are named with a -sample at the end. These files are then meant to be copied to the above named files like contacts.cfg, etc. and modify there contents to be specific to your wishes.
In other words, ditch the "ports" and install from source, since we have no idea what your "ports" of nagios contain or don't contain. Hopefully this is clear. So once more in case it isn't. We don't know anything about your "ports" of nagios. Install from source and follow the nagios installation documentation step by step.
Other than that, contact the "port" maker and ask for installation instructions if you won't install from source code.
Edited Thu Nov 10 2005, 07:54AM ]