I've just submitted v4.0.0 of SNAP Affiliates to the Zen Cart plugins for review; once approved, it can be downloaded here.

This version drops support for Zen Cart versions prior to 1.5.5a and corrects an issue where the affiliate commission payment was disallowed on orders totaling < $1.00.

If you are still running a version of Zen Cart prior to 1.5.5a, please use v3.0.4 of the plugin.