After adding a taxi ad carrier on a covet..... the ad-carrier appear but a car body is disappear!!!!! i dunno what i did wrong....
instantly saw your problem you had hatch.dae in your folder, this is very silly because in the core folder for the hatch there is a file named hatch.dae which is the whole car, so the mod has overwritten the core hatch.dae file I fixed it and renamed the file hatchtaxipart.dae
edit: ninjas D: I didn't even try your mod, but just by looking at this, I can tell you why: You have named your .dae file exactly the same as the base on. The game will load yours (Which only contains your meshes), and not the original one. Rename your dae to something else. Also, 'materials.cs.txt' is not a valid file. And, you cannot have two 'materials.cs' in the same folder (because you can't rename the materials.cs file). I suggest you to make a subfolder ( vehicles > hatch > mymod) and put all your files in there instead. None of them will affect the original ones then. Don't forget to adjust your 'materials.cs' textures path then)