Microsoft released Rollup 4 Version 2 for Exchange so i decided to update my Exchange 2010 Servers and encountered Error code 0×80070643. This is how i fixed it, simple and quick.
Uninstall the following component :Windows Server Windows Management Framework 3.0
Restart the server
Start the installation of Rollup 4 version 2 again.
Restart the server
Install Windows Management Framework again.
Restart the server
After this everything should be fine, i only encountered this on one of the servers.
Hope it helps.