Why does javaFlacEncoder fail for some wav files

Why does javaFlacEncoder fail for some wav files

I am trying to use javaFlacEncoder to encode wav files as flac files.
import java.io.File;
import java.io.FileNotFoundException;
import javaFlacEncoder.FLAC_FileEncoder;
public class OtherConverter {
/**
* @param args
* @throws FileNotFoundException
*/
public static void main(String[] args) throws FileNotFoundException {
// get an encoder
FLAC_FileEncoder flacEncoder = new FLAC_FileEncoder();
// point to the input file
File inputFile = new File("mamasaid.wav");
File outputFile = new File("out2.flac");
// encode the file
System.out.println("Start encoding wav file to flac.");
flacEncoder.encode(inputFile, outputFile);
System.out.println("Finished encoding wav file to flac.");
}
}
It works for some wav files, but not for others. The following wav
converts successfully,
http://www.moviewavs.com/0038067694/WAVS/Movies/Napoleon_Dynamite/pickmeup.wav
But this one gives an error. http://www.rpmswavs.com/waterboy/mamasaid.wav
Start encoding wav file to flac.
Exception in thread "main" java.lang.IllegalArgumentException: Unsupported
Sample Size: size = -1
at
javaFlacEncoder.AudioStreamEncoder.encodeAudioInputStream(AudioStreamEncoder.java:58)
at javaFlacEncoder.FLAC_FileEncoder.encode(FLAC_FileEncoder.java:177)
at OtherConverter.main(OtherConverter.java:21)
Any ideas why?