Minecraft Version: 1.9.4
Inventory Tweaks Version: InventoryTweaks-1.61-dev-53

Crash log:
http://hastebin.com/fuhowiqaxa.vhdl

Affected line in the code:
https://github.com/Inventory-Tweaks/inventory-tweaks/blob/develop/src/main/java/invtweaks/InvTweaks.java#L161

Apparently it's not checking if the stack-trace is an array, it just instantly assumes it