When attempting to add the puzzle-piece for an enchantment by clicking the + with a tool from Adventurers Toolbox, I get this error.

There appears to be no check for having no enchantments available here:

https://github.com/Vazkii/Quark/blob/c09dab8115888e4c11f852a4257081e18636105f/src/main/java/vazkii/quark/oddities/inventory/EnchantmentMatrix.java#L141

The solution would be to have a simple total weight check beforehand, and have a no-op case in that situation.