Great, I’m glad you got them extracted!
Yeah, I see your problem and that’s my fault, so I apologize. I didn’t take into account that everytime you build your mod, you’d have to replace the .arc file. My advice is, you should just extract the .tex files I mentioned and put them in your “settings” folder.
Here’s the deal with the Asset Manager and the .arc file:
It’s looking for source files to create the assets and then, ultimately, the .tex files from. These would be .psd (or .tga) files, which is what you would Auto-Create Asset ► Bitmap with. Then the AM would be able compile an .arc file correctly.
The TexViewer.exe allows you to save a .tex file as a .psd, as well as other formats, for editing.