Be sure that the directory <pgm3>/tmp is writeable for the user of the webserver (e.g. wwwrun.www or www-data.www-data)
Make something like "chown -R wwwrun.www tmp"

Hint: you need the packages php-gd and gnuplot to see the graphics

Look at the wiki on http://www.fhemwiki.de. In the future there will be the most of the Documentation.

All the other Documentation of pgm3 is there:
http://www.martin-haas.de/fhz

Enjoy it :-)

Martin Haas
fhz@martin-haas.de