so, this update rollup installation is only failing for the client machine or you just wanted to install that only for the client machine and not for server . if it is only failing for the client machine even though the above steps are applicable . go to the program and features repair the Outlook client from there and post that uninstall the other update rollup re-install UR6 and then Ur13 . it's always recommended to have same update rollup on both client and server .
Thanks,
Mohammad