how do i scroll through 100 photos in UIScrollView in IPhone

Question

I'm trying to scroll through images being downloaded from a users online album (like in the facebook iphone app) since i can't load all images into memory, i'm loading 3 at a time (prev,current & next). then removing image(prev-1) & image (next +1) from the uiscroller subviews. my logic works fine in the simulator but fails in the device with this error: [CALayer retain]: message sent to deallocated instance what could be the problem below is my code sample

- (void)scrollViewDidEndDecelerating:(UIScrollView *)_scrollView 
{
    pageControlIsChangingPage = NO;
    CGFloat pageWidth = _scrollView.frame.size.width;
    int page = floor((_scrollView.contentOffset.x - pageWidth / 2) / pageWidth) + 1;

    if (page>1 && page<=(pageControl.numberOfPages-3)) {
        [self removeThisView:(page-2)];
        [self removeThisView:(page+2)];
    }

    if (page>0) {
        NSLog(@"<< PREVIOUS");
        [self showPhoto:(page-1)];
    }

    [self showPhoto:page];
    if (page<(pageControl.numberOfPages-1)) {
        //NSLog(@"NEXT >>");
        [self showPhoto:page+1];
        NSLog(@"FINISHED LOADING NEXT >>");
    }
}

-(void) showPhoto:(NSInteger)index
{
    CGFloat cx = scrollView.frame.size.width*index;
    CGFloat cy = 40;

    CGRect rect=CGRectMake( 0, 0,320, 480);
    rect.origin.x =  cx;
    rect.origin.y = cy;
    AsyncImageView* asyncImage = [[AsyncImageView alloc] initWithFrame:rect];
    asyncImage.tag = 999;
    NSURL *url = [NSURL URLWithString:[pics objectAtIndex:index]];

    [asyncImage loadImageFromURL:url place:CGRectMake(150, 190, 30, 30) member:memberid isSlide:@"Yes" picId:[picsIds objectAtIndex:index]];

    [scrollView addSubview:asyncImage];
    [asyncImage release];
}

- (void) removeThisView:(NSInteger)index
{
    if (index<[[scrollView subviews] count] && [[scrollView subviews] objectAtIndex:index]!=nil) {
        if ([[[scrollView subviews] objectAtIndex:index] isKindOfClass:[AsyncImageView class]] || [[[scrollView subviews] objectAtIndex:index] isKindOfClass:[UIImageView class]]) {
            [[[scrollView subviews] objectAtIndex:index] removeFromSuperview];
        }
    }
}

For the record it works OK in the simulator, but not the iphone device itself. any ideas will be appreciated. cheers, fred.