Yes, I'll add it now
It's not an error that will prevent the script from running. It just means that the total sum of Equipment, Food, Potions, Runes, Spade & Misc teleport items add up to an amount greater than 28 for your current settings.
One known cause is using a setup with a 2-handed weapon, and a different setup with a 1-hander and a shield; the script reserves 2 equipment slots for that scenario, even if you start with the 1-hander and shield equipped.
In this case it will just dispose of an item (vial, food, ammo equip) in order to make space for switching, though.