not able to set content type from vocab form

I've installed taxonomy_node and have created the new content type. I already had a list of taxonomy terms - so I went to the vocab edit page and I've tried to set the content type drop-down, but it doesn't save.

My investigation so far seems to make me think the "taxonomynode_{$vid}" isn't being saved properly by the $form['taxonomynode']['taxonomynode_content_type'] field. Is anyone else having this same problem?