Changing sortDescriptors on fetchRequest

[tdmiller7873]

I'm developing a simple navigation-based iPad app. The initial screen shows a TableView with sort buttons in the toolbar at the bottom.

Everything works fine until I try to change the sort order (via the sort buttons) on the fetchRequest and try to reloadData on the tableVIew.

I'm receiving a "EXC_BAD_ACCESS" error message.

Here is the code being called by the sort buttons:

-(IBAction) toolbarSortOrderChanged: (id)sender 
{

    NSLog(@"toolbarSortOrderChanged");

    // Get the fetch request from the controller and change the sort descriptor
    NSFetchRequest* fetchRequest =  self.fetchedResultsController.fetchRequest;
    
    // Edit the sort key based on which button was pressed
    BOOL ascendingOrder = NO;
    UIBarButtonItem* button = (UIBarButtonItem*) sender;
    if ([button.title compare:@"Ascending"]== NSOrderedSame) 
        ascendingOrder=YES;
    else    
        ascendingOrder=NO;
    
    NSSortDescriptor *sortDescriptor = 
    [[NSSortDescriptor alloc] initWithKey:@"periodStartDate" ascending:ascendingOrder];
    NSArray *sortDescriptors = 
    [[NSArray alloc] initWithObjects:sortDescriptor, nil];
    
    [fetchRequest setSortDescriptors:sortDescriptors];
    [sortDescriptor release];
    [sortDescriptors release];
    
    NSError *error = nil;
    if (![[self fetchedResultsController] performFetch:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }
    [error release];
    [fetchRequest release];
    
    [self.timesheetTableView reloadData];
}

The first time the routine is called is crashes on the last line:

[self.timesheetTableView reloadData];

When I comment out this call to reloadData and try running this code, the code will execute fine the first time (although not refreshing the data), but the second time I call this routine (via the same sort button), it crashes on the setSortDescriptors line:

[fetchRequest setSortDescriptors:sortDescriptors];

Yes...I'm still fairly new to iOS and iPad development, but learning quickly. So, any help would be greatly appreciated.

Thanks, T.D.