Handling windows security popup while web page loading using Selenium and AutoIt

I have a web based application with windows security popup displayed as soon the first web page starts loading and the page completes loading only after we provide login credentials.

I have written following script, but it is not going to next code line after selenium.open("/faces/Main"); and finally fails with default timeout error message.

Result console:

Timeout 30000ms

Selenium1 code:

package first;

import java.io.IOException;

import com.thoughtworks.selenium.*;
import org.testng.annotations.*;
import static org.testng.Assert.*;



public class Auth_assign {

private Selenium selenium;

   @BeforeClass
   public void setup() 
   {             
          selenium = new DefaultSelenium("localhost",4444, "*firefox C:/Program Files/FF 7.1/firefox.exe", "http://qa02.mydomain.com");
          selenium.start();
          selenium.windowMaximize();

   }

   @AfterClass(alwaysRun=true) 
   public void stopSelenium() {  
   //this.selenium.stop(); 
   } 




   @Test (description="Authentication pop-up")     
          public void Auth_popup() throws Exception
          {


          System.out.print("Unity page\n ");
          try
          {
          selenium.open("/faces/Main");
          Thread.sleep(10000);

          System.out.print("Window \n ");


          String[] dialog;

          dialog = new String[] { "Login_Dialog.exe","Authentication Required","test46#", "test123"};
          System.out.print( dialog);
          Runtime.getRuntime().exec(dialog);


          selenium.select("//select[@id='qryId1::criteriaItems::content']", "Customer Name");
          selenium.type("//input[@id='qryId1:criterionValue::content']", "Search Company");
          selenium.click("//a[@id='qryId1::search_icon']");
          selenium.waitForPageToLoad("3000");

          selenium.click("//a[@id='t1:0:gl1']");


          } catch (SeleniumException ex) {
        System.err.println(ex.getMessage());
    } catch (Exception e) {
        System.out.println(e.getMessage());
    }


   }      

Login.exe code

;~ ------------------------------------------------------------
;~ Login_dialog.au3
;~ To handle the Authentication Dialogbox
;~ Create By: Gaurang Shah
;~ Usage: Login_dialog.au3 "Dialog Title" "User Name" "Password"
;~ ------------------------------------------------------------
AutoItSetOption("WinTitleMatchMode","2")

if $CmdLine[0] < 3 then
msgbox(0,"Error","Supply all the Arguments, Dialog title User Name, Password")
Exit
EndIf

WinWait($CmdLine[1]) ; match the window with substring
$title = WinGetTitle($CmdLine[1]) ; retrives whole window title
ControlSend($title,"","Edit2",$CmdLine[2]);Sets User Name
ControlSend($title,"","Edit3",$CmdLine[3]);Sets Password
ControlClick($title,"","OK");