I've corrected the formatting of the categories and placed them into the correct parent categories. I have also removed the Cataret County, North Carolina, Slaves category from Mary's profile as she was not a slave.
Before adding a category to a profile, make certain that you have the correct format for the category type. In this case, you had left out the commas between North Carolina and Slave Owners/Slaves. That's been corrected. Also, when adding a category to a profile the category name must be preceded by the word "Category" followed by a colon, like so, [[Category: Carteret County, North Carolina, Slaves]].
When you add a category to a profile that does not yet exist it will be a red link. To complete creation you must click the link and add the parent category and save the page. Before you do that, though, please double check that the category is correctly formatted. If you're uncertain, post in G2G with the tags categorization and categories and someone is always happy to help.