so, not quite sure how this "fixed" it, but I tried running the batch file (without the processed audio) and it installed successfully (and really quick! less than an hour)
I then ran the "TTW_Install.exe" again, and this time no Ogg processing error...installed successfully. I haven't started a game yet so I might run into issues but thought it was worth posting if anyone else gets stuck at the same spot.
Was having the same problem recently. Heard about ttw and figured I'd try it since i love all the fallout games. Started with clean installs of both games a clean install of ttw ran the primary executable with the audio file decoder and wham bass encode error. Tried numerous times to no avail thought I'd google the error message ran across your post about how you fixed it and I tried it as well and it was successful. Thank you!!