Cannot working

Hi,
It is not working properly on me.
When I run the script with perl, I got below error :

Can’t locate LWP/UserAgent.pm in @INC …

I do to install libwww-perl, and I don’t find that error anymore when I run the script with perl.

But, when I follow this manuals, the ‘Status Information’ is shown as ‘null’ on my Nagios browser.

How did you do that actually ?
If possible, please help with a good manuals..

Thanks in advance.