Hello
My nagios is installed (via default) to /etc/nagios
I compile pnp with options;
./configure --prefix=/etc/nagios
but whenever I click on the pnp icon (next to a host or service), I get the message:
Not Found
The requested URL /nagios/pnp/index.php was not found on this server.
Apache/2.2.3 (CentOS) Server at 10.2.1.159 Port 80
Please help 
I think that You will need to reinstall it very well and also scan all the data very well. I hope that You will get the information after click on the pnp icon. I wish that It should be very useful for it.
Its looks that pnp is not configured properly in apache. Make sure that alias for the line is pointing to the right folder.
I hope you get the information then click on the PNP. I hope it would be very useful for this. Make sure the alias line shows the correct folder. I think you should install well, and also check all the data well.
Be sure that line is pointing in the correct folder Make Alias. I think you’re very well established and it also will need to scan all the data very well. I hope that after you click on the icon information will be PNP.