The graphing software needs to be able to open files via URL reference. To enable this the following option in the "php.ini" file needs to be turned on :-
Once the php.ini has been changed the web server will need to be restarted before the change takes effect.
On Linux / Unix machines the php.ini can usually be found in the /etc/ directory.
On Windows machines the php.ini file is located in the directory where PHP was installed ( usually c:\PHP\ or c:\Program Files\PHP\ )
The phpinfo() function can be used to easily find the location of the php.ini file. create a PHP page with the following code:-
Save this in one of your web directories as "phpinfo.php" and then access it via your browser.
The broswer will display a whole range of information about your server and your PHP configuration.
In the top section you should see an item "Configuration File (php.ini) Path" which gives the location
of the php.ini file.