I've followed these steps. I'm currently level 55 construction and making Oak Larders up to level 91. Even with the inventory setup exactly the same due to the script not being fast enough eventually I have a full inventory + a full butler and then the script keeps talking to the butler but he won't give any planks away since the inventory is full.
I can't view the setting up the script on your post, but the script is slowish, can i speed it up a little bit?
Edit: Due to the script being slow the script bugs out where it only wants to talk to the butler with a full inventory and the butler has a full inventory