integrate core plot

hi guys i want add CorePlotGallery in my project but i cant do because when i want call RootViewController.m in my menu i have bug this my function:

- (IBAction)statistic:(id)sender { 
    RootViewController *detai= [[RootViewController alloc] initWithNibName:@"RootViewController" bundle:nil]; 
    [self.navigationController pushViewController:detai animated:YES]; [detai release]; 
}

and the bug exactly is here

plotItem = [[PlotGallery sharedPlotGallery] obj开发者_StackOverflowectAtIndex:indexPath.row];
    cell.imageView.image=[plotItem image];
    cell.textLabel.text = plotItem.title;