Youre doing something wrong bro, or thinking something incorrectly. I dont know why youre thinking of having to do something special with the audio. You DONT.
You just either ripp in FILE mode or in ISO mode. If you ripp in ISO mode, then you just mount the ISO and can play the dvd. In file mode, you just ripp all the files to a FOLDER, then you can play it by loading the main ifo in DVD software player.
Ripping the audio out, even if you did that, it is NOT going to play when you play the vob files. The AUDIO is inside the vob files, compiled with the video. THe only reason to be ripping out audio, is if you are going to be downsampling the video and recompiling it back later. IE: using CCE method or something similar.
There should NOT be any audio folder with audio in it or anything like that.
*NOTE*: There is a AUDIO_TS folder on the DVD sometimes, but there should NEVER be anything in the folder if thats what is throwing you off. Burning a dvd you should always have a VIDEO_TS folder and AUDIO_TS folder, but there should never be anything in the AUDIO_TS folder.