OpenIV Cannot Edit .ymt File

oCantStopMe

Game Version: GTA V (1.50) [Social Club] {1.0.1868.1}
Mod I'm attempting to Install: https://www.gta5-mods.com/vehicles/1998-mercedes-benz-c200-elegance-w202-fl-add-on-replace-extras-tuning

Hello, I am currently attempting to install this car mod.
However, when I attempt to edit the "carvariations.ymt" file - OpenIV presents the following error message:

alt text
Any ideas? Cheers.