Starting network monitor: nagios
CONFIG ERROR! Start aborted. Check your Nagios configuration.
Please take no offense, but could it be anymore vague? Is there anyway to tell where the error is?
Did you try nagios.sourceforge.net/docs/1_0/
The docs are quite clear on how to check the configs. If you haven’t read the docs, please do so. If you have further trouble after that, let us know. The error you got sounds self explanatory. Check your nagios configuration. One of the .cfg files is not correct, and if you had tested the nagios installation per the docs, it would tell you exactly what config file is broken.
So, test the nagios installation by using the proper command line and option switch and it will tell you what is broken.