Hi Jdbro,
I cannot see beneath the error if you have a different type of animation already implemented, but you can easily start “fresh” by clicking on “Remove all samples” in the Samples window that you have highlighted in red. At that point you should not have an issue if all animations are of the same Additive Anim Type as you have donated in the red box above. You may need to save these first, as they have an asterix showing that they need to be saved. Lastly, you can send me the project stripped down to just these assets via Private Message. As it stands, it looks like you have it set up correctly.