Missing "new category" Button

Hi All.
I don't seem to have a "new category" button.
I read this http://www.zen-cart.com/forum/showthread.php?t=40405 so I think I know where it should be (in admin -> catalog -> categories/) but it's not there!
Any ideas where it's gone?
Cheers, D.

Ah, hold on. I have this error at the bottom of the page:

WARNING: You have Products in the Top Level Category. This will cause pricing to not work properly in the Catalog. Products found: 9

(I didn't add them!) And I've just read this:
http://www.zen-cart.com/forum/showthread.php?t=39001
Which says:

The Categories hold Products or Categories ... never both ...
To stop errors of adding both to a Category ...
When a Category holds a Category, the New Product button will vanish ...
When a Category holds a Product, the New Category button will vanish ...
Otherwise you will have search errors, pricing errors, etc.
So that would explain it. I guess I have to massage the database to get them in a category and get the "new category" button back?