I think one of my mods (assume it's homeworld redux) must have some dodgy item definitions which work ok in the game, but RF is having problems with it.

I get "Error while loading recipe prototype "rf-seeder-module-01" (recipe): Difficulty normal: Item ingredient can't have count of 0"

Uhh... yes it does seem to be doing something weird. So it uses a function to make seeder module items, numbered 1-5, and gives it 2 recipes: a hidden one which requires itself and produces nothing (used only by seeders), and a second, actual assembly recipe that requires some ingredients, and creates 2 of the modules.

Okay, I think I see the fix. Should be up soon.