I had these lines of code within some of the actions run by some of my entities in my game. After I updated my gamestudio to version 8.10.3, I had to comment out all such lines because while the game still runs, the moment it tries to create any entity that has any material assignment within its code, I get an Error E1520 that says "Structs inconsistent - MATERIAL".
The "mtlFX.c" file in my include folder has the following properties:
Date modified: 12/22/2013 4:29pm
Size: 26.8kb
I have not tampered with this file in any way at all. Is there something I'm doing wrong?

I remember there exists some changes after version 8.10.
For example, mat_model was used in earlier versions, but for newer version you must rename in mtl_model.

But since I haven't made any changes whatsoever to the default files in the include folder, and I haven't written a single line of shader code myself, I should be able to simply assign some of the shaders that come with gamestudio to my entities. How do I do that?

This is C-Script/Wdl section, did you are trying mix C-Script with lite-C?

No, I created a new topic and posted without checking/changing any of the defaults apart from selecting the "Add this thread to my Watched Topics." checkbox. It must have been automatically added to the C-Script section. How can I change that?

Guys, I still haven't found the root of the problem. I can't assign my models the default shaders that came with Gamestudio

Found it! The include folder was ok, but I had to copy the files from the include folder into my project folder and overwrite the old files.