edit - haa, it is always right after you post on a forum that you stumble upon the obviousness of your error. in case anyone searches and brings this up, make sure you’re actually USING the uid set in nagios.cfg to run the program. 
i’ll put on the dunce hat and go on my merry way now.
hello, i am installing nagios on a redhat enterprise linux 4 box, and while the preflight check is error free, when i run nagios via:
./nagios /usr/local/nagios/etc/nagios.cfg
I get:
Warning: Cannot open log file ‘/usr/local/nagios/var/nagios.log’ for writing
Warning: Could not set effective GID=503
Warning: Cannot open log file ‘/usr/local/nagios/var/nagios.log’ for writing
Warning: Unable to change supplementary groups using initgroups() – I hope you know what you’re doing
Warning: Cannot open log file ‘/usr/local/nagios/var/nagios.log’ for writing
Warning: Could not set effective UID=503
Warning: Cannot open log file ‘/usr/local/nagios/var/nagios.log’ for writing
Failed to drop privileges. Aborting.
I have a feeling this is mostly a problem due to me still being unfamiliar with linux. Currently everything in /nagios and under is owned by those uid/gid’s, with rwx permissions. Any help figuring this out would be much apprecciated.
edit: forgot to mention, i’m running wthout -d so that i can see why it is not running(as per the html instructions)
Edited ]