Nagios Problem

Hi Everybody,
I have configure nagios server and client on my lab machines which are running under VMWARE.
Now i would like to know how the nagios working in my systems. For that, what i did is i filled up the / partition with some data above 95% in client. But still it is report good status report in disk paramater in nagios server about client.
So, then
I had manually given this below command
check_local_disk!20%!10%!/ in nagios server. I got below error

check_local_disk/usr/local/nagios/libexec/check_nrpe -H 192.168.0.193
bash: check_local_disk/usr/local/nagios/libexec/check_nrpe: No such file or directory

Please, can any body tell me where i did mistake in nagios server.

Thanks.