Hi Tony,
The following error messages will continue to appear if the drum counter was not reset when you replace the drum unit with a new one.
I would suggest you to try the steps in the article and check if it helps.
If the issue persists, I would suggest you to contact Brother Support for further assistance.
http://www.brother-usa.com/support/CustServ.aspx
Hope this information helps. Reply to the post with updated status of the issue to assist you further.