java.io.FileNotFoundException: Could not find file HVORFOR?

Flg kodestump ligger på min GUI.
Den skal bruges til at sætte hhv. et input og et output directory som der skal læses/skrives filer til.

directory navnet gemmes i enten String inputdir, eller String outputDir som er globale variabler.

nogle gange går det fint... andre gange får jeg en exception ala den indsat nederst... men hvorfor?

selve metoden:

  private void chooseDirectory(String choosertitle, boolean isInputDir)
  {
    JFileChooser chooser = new JFileChooser(new File(inputDir));
    chooser.setCurrentDirectory(new java.io.File("."));
    chooser.setDialogTitle(choosertitle);
    chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
    if (chooser.showOpenDialog(this) == JFileChooser.APPROVE_OPTION)
    {
      if(isInputDir)
      {
        inputDir=chooser.getCurrentDirectory().toString();
        inputLocationTextField.setText(inputDir);
      }
      else
      {
        outputDir=chooser.getCurrentDirectory().toString();
        outputDirTextField.setText(outputDir);
      }
    }
  }


Exception der kastes:

FileSystemView.getShellFolder: f=.

java.io.FileNotFoundException: Could not find file C:\jdev1012\jdev\mywork\Diplom\Project\.

    at sun.awt.shell.Win32ShellFolder2.parseDisplayName(Win32ShellFolder2.java:580)

    at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Win32ShellFolderManager2.java:40)

    at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Win32ShellFolderManager2.java:36)

    at sun.awt.shell.ShellFolder.getShellFolder(ShellFolder.java)

    at javax.swing.filechooser.FileSystemView.getShellFolder(FileSystemView.java:486)

    at javax.swing.filechooser.FileSystemView.getFiles(FileSystemView.java:409)

    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(BasicDirectoryModel.java:194)

java.lang.NullPointerException

    at javax.swing.filechooser.FileSystemView.getFiles(FileSystemView.java:412)

    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(BasicDirectoryModel.java:194)

FileSystemView.getShellFolder: f=.

java.io.FileNotFoundException: Could not find file C:\jdev1012\jdev\mywork\Diplom\Project\.

    at sun.awt.shell.Win32ShellFolder2.parseDisplayName(Win32ShellFolder2.java:580)

    at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Win32ShellFolderManager2.java:40)

    at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Win32ShellFolderManager2.java:36)

    at sun.awt.shell.ShellFolder.getShellFolder(ShellFolder.java)

    at javax.swing.filechooser.FileSystemView.getShellFolder(FileSystemView.java:486)

    at javax.swing.filechooser.FileSystemView.getFiles(FileSystemView.java:409)

    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(BasicDirectoryModel.java:194)

java.lang.NullPointerException

    at javax.swing.filechooser.FileSystemView.getFiles(FileSystemView.java:412)

    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(BasicDirectoryModel.java:194)

FileSystemView.getShellFolder: f=.

java.io.FileNotFoundException: Could not find file C:\jdev1012\jdev\mywork\Diplom\Project\.

    at sun.awt.shell.Win32ShellFolder2.parseDisplayName(Win32ShellFolder2.java:580)

    at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Win32ShellFolderManager2.java:40)

    at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Win32ShellFolderManager2.java:36)

    at sun.awt.shell.ShellFolder.getShellFolder(ShellFolder.java)

    at javax.swing.filechooser.FileSystemView.getShellFolder(FileSystemView.java:486)

    at javax.swing.filechooser.FileSystemView.getFiles(FileSystemView.java:409)

    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(BasicDirectoryModel.java:194)

java.lang.NullPointerException

    at javax.swing.filechooser.FileSystemView.getFiles(FileSystemView.java:412)

    at javax.swing.plaf.basic.BasicDirectoryModel$LoadFilesThread.run(BasicDirectoryModel.java:194)