The lettering is busted because the mod is slightly outdated. It still works and functions, just remove the lettering off the hood.
I got the letters working again by copying over 3 .dds-files from an older version of the game I still have on another computer. The 3 files that can't be loaded are: barstow_lettering_d.dds barstow_lettering_n.dds barstow_lettering_s.dds from the barstow.zip in the game files. If you look in the game files from 0.37, these .dds-files don't exist anymore in the form this mod needs. If it is allowed for me to upload the 3 missing files here, I would do so. They just need to be copied to the following folder in your user account folder in Windows: 'AppData\Local\BeamNG\BeamNG.drive\current\vehicles\barstow' (the 'vehicles' and then 'barstow' folders in 'current' probably don't exist yet, so just create them).