You may not be passing any arguments to the program. This is a console application designed to run once and then exit. Most applications like this work best when run through Window's command prompt. You can shift click on a folder and select Open Command Prompt (or cmd) window here. (Does not work in library folders). After that call
"WAVToXNBSoundConverter v0.1.exe" (quotes are important if spaces are in the name) and it should output instructions on how to use the program. Hope this helps.
(Protip: Have all of the files in the same folder you open the command prompt in, that way it can identify the files without you having to provide full paths)
Many programs (such as ffmpeg.exe) function this way, so it's helpful to remember this information for the future.