Do you actually have the mod?
You may need some files from the common folder as well as those from the actual Benetton folder.
The best way to check is to open one of the Benetton shapes with GP4Builder. You'll then be able to see the textures associated with that car.
Those are the ones you will need.
Races: 163 - Wins: 23 - Pole Positions: 24 - Fastest Laps: 22
Season 9: Constructors' Champions