Status UNKNOWN

hello,

I have installed nagios-plugins-1.4.14 and nrpe-2.12 to a RedHat Enterprise L5
followed NRPE official document and http://www.thegeekstuff.com/2008/06/how-to-monitor-remote-linux-host-using-nagios-30/ to make it work.

Now on the nagios server side i see all status information shown as UNKNOWN, what i am missing any help would be appreciated.

Nagios server version is 3

Regards,
Emre