Roles - Permissions

I created a specific tables to register users in Drupal, but im continue using the 'users' and the 'users_roles' table from drupal.

I have a big problema, i have 5 roles (admin, colab, c_blog, c_forum, c_book) and when i register a new user im created the association of the users withe roles through the 'users_roles' table.

Example:

The uid of new user is 5, so my users_roles table is:

uid rid
5 2
5 3

In other words, my user (uid = 5) have permissions to create and edit blogs (c_blog) and fforums (c_forum). But when this user trying to create the contents, the drupal it returns the message that the user do not have access to this pages.

Drupal using other tables without users_roles to configurate user permissions?

Thanks.

Marcus