After installing, where is the newsletter? I've activated it in the tab and in plugins. On one site there is no tab in the profile. On another site the tab is in the profile but error message says newsletter is not installed.

Whats not being configured correctly or what should I look for that is missing .....

Sounds to me like you have not yet installed the News Letter Component. All that you have discribed in your post is to alow the newsletter component to be displayed through CB but you must still install the actual newsletter.