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


Hint: you need the package php-gd to see the graphics

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


Enjoy it :-)