Unable to update

[Nick]

Message #0: The system cannot find the file specified
Source #0: System
Target Site #0: Boolean StartWithShellExecuteEx(System.Diagnostics.ProcessStartInfo)
Stack Trace:
  at System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo)
  at System.Diagnostics.Process.Start()
  at System.Diagnostics.Process.Start(ProcessStartInfo startInfo)
  at System.Diagnostics.Process.Start(String fileName)
  at Little_Registry_Cleaner.UpdateDlg.buttonDownload_Click(Object sender, EventArgs e)
  at System.Windows.Forms.Control.OnClick(EventArgs e)
  at System.Windows.Forms.Button.OnClick(EventArgs e)
  at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
  at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
  at System.Windows.Forms.Control.WndProc(Message& m)
  at System.Windows.Forms.ButtonBase.WndProc(Message& m)
  at System.Windows.Forms.Button.WndProc(Message& m)
  at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
  at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
  at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)

This could be a problem in only Windows XP