Let's see:
-I set it up under /usr/local/
-I used the latest distribution 0.5
-I did not install rrdtool as that already came with system monitor. So the path to it under BINDPATH is /usr/bin when you configure hotsanic
-I had already installed imagemagick to run Drupal from here:
http://mirror.contribs.org/smeserver/contribs/star/mitel/contrib/image-magick/-I added a custom template to init.d so the /usr/local/rrdgraph starts automatically upon reboot.
-This new version differs a little bit from the tutorial on the because a few paths to the application are different (example: old one uses /settings.all and the new one uses /var/settings/) but they're only few.
In 6.5 if you don't have these packages installed (rrdtool or imagemagick) the tutorial should get you done. Or move to 7Beta1 and experiment with the great power of YUM.
Now, this is just my personal opinion about the accounting capabilities:
If you're trying to account for clients on you net, there are much better packages than this. Check this one out:
http://no.longer.valid/phpwiki/index.php/Install%20ObjectPlanets%20Network%20Probe%20How%20To