Error when adding document types

In a new install of Drupal and the module, there are no content types listed on the Document module admin page at /admin/structure/document. When I try to add a new content type, a pop-up displays with the word "Error" in it. When I look at my Chrome console, there are no visible Javascript errors. I've tried it with both JQuery 1.5 and 1.7 enabled and the same thing happens.

Oddly enough, when I go to my Document module in an older install, all the old document types ARE in there and I am allowed to add new ones, however I can't, then, remove them. I get the same "Error" error.