|That syntax of if exist works in xp, unless "ift" wasn't just a typo added in at post time.|
You may be able to use dir instead:
>nul 2>&1 dir /ad "D:\WindowsImagesMyBackup\" && ren "D:\WindowsImagesMyBackup" "%date:/=.%"
Provided your %date% doesn't contain any other illegal character, with the exception
of "/", and there isn't any files or folders named what %date:/=.% expands to.