Why does my application crash with the following error? - objective-c

Question

When I scroll my table view up and down, after about 6-8 times my application crashes and I get the following in debug window:
myapp[250:207] *** -[NSIndexPath row]: message sent to deallocated instance 0xdd0eab0
Here is my code:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// Return the number of rows in the section.
return [remoteRecipientItems count];
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"RemoteRecipientItem";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
NSUInteger row = [indexPath row];
NSUInteger oldRow = [lastIndexPath row];
// Configure the cell...
[[cell textLabel]setText:[remoteRecipientItems objectAtIndex:[indexPath row]]];
cell.accessoryType = (row == oldRow && lastIndexPath !=nil)? UITableViewCellAccessoryCheckmark : UITableViewCellAccessoryNone;
return cell;
}
#pragma mark -
#pragma mark Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
int newRow = [indexPath row];
int oldRow = (lastIndexPath !=nil)?[lastIndexPath row]:-1;
if (newRow != oldRow) {
UITableViewCell *newCell = [tableView cellForRowAtIndexPath:indexPath];
newCell.accessoryType = UITableViewCellAccessoryCheckmark;
UITableViewCell *oldCell = [tableView cellForRowAtIndexPath:lastIndexPath];
oldCell.accessoryType = UITableViewCellAccessoryNone;
lastIndexPath = indexPath;
}
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
#pragma mark -
#pragma mark Memory management
- (void)didReceiveMemoryWarning {
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];
// Relinquish ownership any cached data, images, etc. that aren't in use.
}
- (void)viewDidUnload {
// Relinquish ownership of anything that can be recreated in viewDidLoad or on demand.
// For example: self.myOutlet = nil;
remoteRecipientItems = nil;
remoteRecipientID = nil;
xmlData = nil;
lastIndexPath = nil;
}
- (void)dealloc {
[remoteRecipientItems release];
[remoteRecipientID release];
[xmlData release];
[lastIndexPath release];
[super dealloc];
}

Answer 1

You don't own the indexPath variable, so you need to retain it.
Try replacing this:
lastIndexPath = indexPath;
With this:
lastIndexPath = [indexPath retain];