Problem is gone,
i have copy the current cars.wad on desktop and paste the original cars.wad in the gp4folder. Then i overwrite the original with my current cars.wad and now it works again. no idea why but it works.
A strange problem is, when i change something in the team editor, my cars.wad goes very heavy (1.79Gb)...even with the original cars.wad, one change (driver speed) and apply all changes, bähm 1,79Gb)?!