There is a speciffic german symbols in descritopn of the mod.
How to fix:
1. Unzip mod from Armor-MK4_1.0.1.zip
2. Open file info.json
3. Delete or replace non ascii symbols in "description" : Noch groe >ß < ere, noch bessere Power-Ruestungen; mit einem gigantischen Raster (40x40) und einem riesigen Inventarbonus (+200).

you can also change the .json file format from ANSI into UTF-8 that also fixes the buged description window in game and actually .json files should only support UTF formats so it would be nice if the dev of this mod could change that in general