Program: 8839
Project: 8839
Buggy source:
/** 
 * Extract and copy DK II sounds & music
 * @param dungeonKeeperFolder DK II main folder
 * @param destination Destination folder
 */
private void convertSounds(String dungeonKeeperFolder,String destination){
  if (!ConvertProcess.MUSIC_AND_SOUNDS.isOutdated()) {
    return;
  }
  logger.log(Level.INFO,"String_Node_Str",destination);
  updateStatus(null,null,ConvertProcess.MUSIC_AND_SOUNDS);
  AssetUtils.deleteFolder(new File(destination));
  String dataDirectory=PathUtils.DKII_SFX_FOLDER;
  final List<File> sdtFiles=new ArrayList<>();
  File dataDir=null;
  try {
    dataDir=new File(ConversionUtils.getRealFileName(dungeonKeeperFolder,dataDirectory));
    Files.walkFileTree(dataDir.toPath(),new SimpleFileVisitor<Path>(){
      @Override public FileVisitResult visitFile(      Path file,      BasicFileAttributes attrs) throws IOException {
        if (attrs.isRegularFile() && file.getFileName().toString().toLowerCase().endsWith("String_Node_Str")) {
          sdtFiles.add(file.toFile());
        }
        return FileVisitResult.CONTINUE;
      }
    }
);
  }
 catch (  IOException ex) {
    String msg="String_Node_Str" + dataDirectory + "String_Node_Str";
    logger.log(Level.SEVERE,msg,ex);
    throw new RuntimeException(msg,ex);
  }
  int i=0;
  int total=sdtFiles.size();
  for (  File file : sdtFiles) {
    updateStatus(i,total,ConvertProcess.MUSIC_AND_SOUNDS);
    i++;
    SdtFile sdt=new SdtFile(file);
    String path=file.toString().substring(0,file.toString().length() - 4);
    Path relative=dataDir.toPath().relativize(new File(path).toPath());
    String dest=destination;
    dest+=relative.toString();
    sdt.extractFileData(dest);
  }
}

Fixed version (ground truth):
/** 
 * Extract and copy DK II sounds & music
 * @param dungeonKeeperFolder DK II main folder
 * @param destination Destination folder
 */
private void convertSounds(String dungeonKeeperFolder,String destination){
  if (!ConvertProcess.MUSIC_AND_SOUNDS.isOutdated()) {
    return;
  }
  LOGGER.log(Level.INFO,"String_Node_Str",destination);
  updateStatus(null,null,ConvertProcess.MUSIC_AND_SOUNDS);
  AssetUtils.deleteFolder(new File(destination));
  String dataDirectory=PathUtils.DKII_SFX_FOLDER;
  final List<File> sdtFiles=new ArrayList<>();
  File dataDir=null;
  try {
    dataDir=new File(ConversionUtils.getRealFileName(dungeonKeeperFolder,dataDirectory));
    Files.walkFileTree(dataDir.toPath(),new SimpleFileVisitor<Path>(){
      @Override public FileVisitResult visitFile(      Path file,      BasicFileAttributes attrs) throws IOException {
        if (attrs.isRegularFile() && file.getFileName().toString().toLowerCase().endsWith("String_Node_Str")) {
          sdtFiles.add(file.toFile());
        }
        return FileVisitResult.CONTINUE;
      }
    }
);
  }
 catch (  IOException ex) {
    String msg="String_Node_Str" + dataDirectory + "String_Node_Str";
    LOGGER.log(Level.SEVERE,msg,ex);
    throw new RuntimeException(msg,ex);
  }
  int i=0;
  int total=sdtFiles.size();
  for (  File file : sdtFiles) {
    updateStatus(i,total,ConvertProcess.MUSIC_AND_SOUNDS);
    i++;
    SdtFile sdt=new SdtFile(file);
    String path=file.toString().substring(0,file.toString().length() - 4);
    Path relative=dataDir.toPath().relativize(new File(path).toPath());
    String dest=destination;
    dest+=relative.toString();
    sdt.extractFileData(dest);
  }
}