So, odd issue.
I'm running CentOS 6.5 x64, and NRPE latest stable from EPEL.
Ran into an issue where I can only start nrpe via service (which is what chkconfig uses) by running it sh first.
service nrpe start fails but
sh service nrpe start works fine.
This is what the log shows:
nrpe: Unable to open config file '/etc/nagios/nrpe.cfg' for reading nrpe: Config file '/etc/nagios/nrpe.cfg' contained errors, aborting...