If he is getting the error message, "There appears to be no .uis file in this skin. Are you sure it is a WindowBlinds skin?" then he has to be using WindowBlinds to apply the skin. Only with windowBlinds installed would you get that particular error message.
WILDA PARKER, what skin are you trying to open? Is this happening with just one skin or with several? Does the file have a .wba file extension or a .zip extension? If it is a zip, have you tried unzipping it to a folder to be sure that a .uis file is in fact present in the file? What version of Windowblinds are you using? The more information you give us, the easier it will be to help you.