That's an add_cat_to_cat - I asked you for an add_prod_to_prod. But since cat 36 seems to work, please try
Code:
function setup() {
$this->add_cat_to_cat(36,36,"%", 15);
}
} // closing paren for class
I suspect that will work, which means that the real issue is with categories only, and you need to look at the help on categories
http://www.thatsoftwareguy.com/zenca...ry_issues.html
to see how they work and what can go wrong.