Just a quick Doc update to avoid platform confusion

I spent several hours chasing **NRPE: Unable to read output** errors when attempting to run this script.  The script seemed to work fine when running on the command line, but when Nagios Server executed the check through check_nrpe, that error was produced.  Finally tracked it down to that lib path used in the script.

Great script, this is definitely going to help us tune our php driven learning application servers.  Thanks for your hard work on it!