Profiles with custom data don't appear on Drupal new user registration forms

PROBLEM:
I created custom data types, and then used them for a "profile" that should appear on the new user registration page for Drupal (5.1). It may in fact have appeared there for a little while. However, pehaps because of some change I made, the profile with the custom data will simply not appear on the user registration page. It appears, correctly, on both the authenticated user account page, and it can be edited from there, but I really need to collect this data upon registration.

What is strange is that the initial "name and address" profile does appear on the registration form, but all attempts to add fields based on custom data to the name and address profile fail. The profile continues to display, but I am not able to change its content.

RESPONSE:
Due to our new ACL permissioning system, you need to enable "access all custom data" for anonymous users.

If you do use ACL's you have more fine grained control over what field gets displayed to whom and when.

Source