Don't fully understand your statement but if you are using AI it is possable for the AI to use your skin. If how ever you mean in rhe Drivers list then you you may have a dupe ini??
it does make it easier... or we could all pop around - make sure the kettle is on and you have enough mugs available
serious though i think i know what you are seeing as others have pointed out.
i have my custom skin and i select that to drive with hence my entry is up there Keith Peppiatt... when the starting line up was chosen the computer in its infinite wisdom decided to put another Keith Peppiatt in the line up ie: the one in the skin file. the game doesn't appear to have enough intelligence to piece together that as you have chosen that skin that you don't want another one appear on the grid, but i guess thats the joy of random selection... it is totally random.
Well start with Image depending on its size and format you can either attach it or if you wish you can host it via your webspace or find a image host such as imageshack.
Could it be a vista problem? Short and sweet "No"
Ok ways to get duplicates :
One: install a custom skin of an allready pesent driver within the game.
Two: have a duplicate INI file that for the same driver
Three: ??