Categories and Tags not working

I have just launched a store on at.

I use categories to display the content on

The products display on because I am displaying all products.

For some reason, when I go in to assign categories or tags, it will not save the information. The categories show up as blank when I go into a product. I cant create categories on the product category page either.

I have uninstalled and reinstalled the plugin. I have a backup of everything. Is there a way I can delete all the plugin data so I can start from scratch?