Unable to get UIAlertView Delegate methods

Question

Hi,

I have a view controller where i am displaying a alert view from another class. The coding of alert view is not in View controller. The alert view is visible but i am not able to call the delegate method in the view controller as the class in which i created is an NSObject class. Can some one please guide me how to set the delegate of alertview????

DisplayCouponViewController *dis = [[DisplayCouponViewController alloc] init];
dis.darkView.hidden = TRUE;

UIAlertView *AlertCouponDownload = [[UIAlertView alloc] initWithTitle:@"Coupon Downloaded" message:@"" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
AlertCouponDownload.delegate = dis;
[AlertCouponDownload show];
[dis release];

Tried above code but it gives error

Thanks