I would like a user to see a message on their user page if they haven't created a profile (custom content type made with CCK)

In rules, I created:

on event - user visits user page. on condition - ?? action - show message

It's the condition I'm having a problem with. "Has content type" is not in the available conditions, but underneath, one of the "non configurable" conditions is:

Content has type Unavailable argument: Content

which is exactly what I need. How do I get that condition to become usable in my rule? The help text states: If you want to use any of these conditions, you must first add some action that adds variables of this kind in a previous rule, or have an event that passes the required variables.

I'm not really sure what that means.

Regards

Neil