I'm getting an error when clicking on 20 Point Wizard Tokens in my inventory to try to add them to my currency. Because of this, I can't add them, or do anything at all with them.

It sounds like you are doing something with multiple tabs where the system is referring to the exact same item over and over again (not a duplicate of the same item) or you might be trying to refresh the inventory item page without going back to your inventory first.

Anyways, there is a much easier way around this. Just cash them all in at the Wizard Token Exchange

Ah, that did work, thank you. I've used multiple tabs for the inventory system before, but I didn't realize that would mess things up--I won't do that from now on. I appreciate the assistance!