Thank you for the suggestions. I think it is a SpellBinders die, and I plan to contact them. I don't think the store I bought it at will do a refund, as it was a final sale. However, if the product they sold was defective, I'm not sure what their policy is. So far, they seem to be a great store.
Okay, can somebody please explain what a shim (metal or otherwise) is? And what is swimming? And how can it possibly wreck your die-cutting machine?