There are issues with ats2wav and XP. Anyway the syntax is command line:
ats2wav D:\AUDIO_TS\ATS_01_0.IFO
typed in a DOS command line window, after copying ats2wav.exe into the destination folder. You must "cd" into this folder in the command window prior to typing the above line.
My try was an utter failure, with an error message requiring the missing cygwin1.dll
There are a handful of shareware apps here :
http://www.01download.net/search/90813/Geewhizz, strange there aren't more DVD-A rippers out there, for all the potential demand for it!