log.info("retreiving '" + files.length + "' manual transferred data files from directory '" + subDir.getAbsolutePath() + "'");
// alphabetical order guarantees correct sequence.
TreeSet set = new TreeSet();
for (int i=0; i < files.length; i++)
set.add(files[i]);
files = (String[])set.toArray(new String[set.size()]);
for (int i=0; i < files.length; i++) {
File file = new File(subDir, files[i]);
if (!file.exists())
throw new Exception("The entry nr. '" + i + "': file '" + file.getAbsolutePath() + "' does not exist");