I have never copied a game sound track or even a modern game .
I recently tried to help another member do this but so far little success.
Maybe some of the software will work better for you.
MFAudio was the program he used. There are a couple of links in one of my posts to video.help forum that have some instructions.
My end suggestion has been to use a screen capture program to create a audio/video file & use a converter to remove the audio track from that file.
There are many converters & you probably already have one. So I won't suggest one for now.