I installed a fresh instance of Microsoft Dynamics CRM Data Migration Manager. Then I wanted to apply Rollup 8 to it.
Error: DMClient KB971782 is not found
Resolution: First install Rollup 7 update for DM Client (http://www.microsoft.com/downloads/details.aspx?FamilyID=A4893988-7804-4E23-AB58-740441CC696E&displaylang=en) and then you are able to install Rollup 8.