CCK - Missing "Add new field" Link/Tab??

I just installed CCK 5.x-1.6-1 on my new Drupal 5.2 installation. I've used cck extensively before on drupal 4.7...

But now, when I go to the content type screen and try to edit a content type, I seem to be missing the ability to add fields.

The drupal handbook says:
"Choose the option to 'edit' the 'story' type. Once you get to the screen where you can edit the content type, you will see additional tabs that say 'Manage fields', 'Display fields', and 'Add new field'. If you choose 'Manage fields' or 'Display fields' you will see nothing, since you have not yet created any fields, so start by selecting the option 'Add new field'."

I've done exactly that, and - even though it says it's installed (on the admin>modules page) and the "Content Types" screen has a new "Fields" tab (which is empty since I haven't been able to add any) - there is no "Add new field" option...

Any ideas what it might be?

I'm using drupal 5.2, php 5.2.4, MySQL 5.0.45, Apache 1.3 ....

Thanks in advance,

- Jason