this error happens because the physics model have some hard edge normal applied, tri to soften the vertex normals with Normal > soften edge.
save the scene again, and recompile your model, studioMdl should not display that error again. If the message appears again try to apply a freeze transform on the normal of the colision model.
Check the destination directory of the MDL file, or the StudioMDL will not be able to write the files.
In that example the directory props_furniture do not exists on the disk, create the folder and recompile the model should fix the problem.
without an error code, try compiling with HLMV running. ( source vdc )
How to fix : launch Steam if you want to export the texture and /or compile the MDL.
The path set in the maya.env as VPROJECT , do not contains any Gameinfo.txt file.