Why does a serve and a fluiduct not extract creosote oil from coke oven

General rule of mods: Mods generally DO NOT WORK WITH EACH OTHER (unless they're part of one of those group modpacks, like Technic or FTB). The Fluiducts and Tanks work because Thermal Dynamics and OpenBlocks use a common API for fluid transfers, whereas Railcraft does not use it, and thus are not compatible with the ducts or tanks.

Whilst Fluiducts do work with the tanks, the coke ovens do not work with the fluiducts. You have to manually bucket it.