Management Reporter 2012 - RU5 - The specified integration user credentials aren't valid. Verify that the user name and password are correct and that the user is a member of the 'db_datareader' database role.

Run the clearcompanies script. This will remove any "ghost" companies from your DYNAMICS database if there are no corresponding databases for those companies.

You can get the script from here
https://mbs2.microsoft.com/fileexchange/?fileID=d57c52af-2432-486d-9072-e1a1d60563bf

Original Solution:
http://community.dynamics.com/gp/f/32/t/106052.aspx