Presenting Modal View Controller in iOS not working
===

I need to show another view from rootviewcontroller on button click. I have written the following code but it doesnt work. Any ideas why? 

In my app delegate method i have the following code -   

    - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
    {
    self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];
    // Override point for customization after application launch.
    self.viewController = [[[MainMenuViewController alloc] initWithNibName:@"MainMenuViewController" bundle:nil] autorelease];
    
    self.window.rootViewController = self.viewController;
    [self.window makeKeyAndVisible];
    return YES;
    }

Then in my mainviewcontroller i have a button action which is supposed to take me to a different class but it does nothing. Although the button action is working since nslog statements work. Any ideas? 

       LoginViewController * loginViewController = [[LoginViewController alloc]initWithNibName:@"LoginViewController" bundle:nil];
       [self.modalViewController presentModalViewController:loginViewController animated:YES];
    NSLog(@"HE::P");