Target Corpse is broken... I've just set up Summon Zombies like a regular skill, ignore the minion dropdown, that doesn't work either for zombies. I have it set up with a cooldown of 2000 and a priority of 30 (other skill is Summon Skeleton at 20). It doesn't summon every 2 seconds, probably due to corpses not being available but it works 'well enough' for leveling. I have Skeletons set to cooldown of 500 with priority of 20 and that works too.
Also max distance is 40 for all skills, min is 0.
I deleted the default attack entirely from the list of actions in the bot because it was just spamming the hell out of it. This didn't stop that entirely but it works decently.