Having purchased this software after being informed it works with Drupal, the plugin page on the portal says the plugin has only been tested on Drupal 7.8. Does it work on Drupal 6 and if so how does one configure it?
The aMember4 version doesn't (yet), but if I were you I would upgrade to Drupal 7.x either way as Drupal 8 is around the corner.
Unfortunately the site in question is a large production site which will not be ported to Drupal 7 any time soon as it is still too unstable and a number of essential modules to the site are not ported to D7. Without a functional amember system compatible with D6 the project is a non starter i'm afraid.
Contact support, they should be able to assist you. The aMember 3 version was compatible with both versions of Drupal