One more thing: Did you try to hard code some agent in your rule function module (just append into ACTOR_TAB)? Then at least you will know that the rule itself will work in the workflow (bindings etc. have been correctly done).
You don't need to include actor_tab in the binding. Just bind the needed input parameters to your rule from the workflow container. (And if you do the above, then you will know if there is some problem in the bindings, or not).
Regards,
Karri