Need Help with zmodeler to convert a .obj to an propper GTA IV Carmod

[Knaggebacke90]

I´m a Total noob with zmodeler the only thing i know is how to import and i don´t even know if im using the right file.The Problem i have is: i import the file i think is correct but there comes allways an error called :ZModeler is ready. Failed to load multiple material files from "mtllib" instruction. Now trying to load as "Exterior.mtl" so after i noticed that it had an error i troubleshoot and searched a way to tell zmodeler which textures it should use where but i failed and im out of options so. For better Understanding i took some screens:
https://img5.picload.org/image/rcwaopla/unbenannt.png

 

 

 

Thanks

(sorry for my Bad English)

Edited May 9, 2017 by Knaggebacke90