(null) values in NSMutableArray after inserting an NSMutableDictionary

Question

I'm using an NSXMLParser to grab data and build an array of dictionaries with some information on a set of photos. Whenever I attempt to add a dictionary to the array, the value is always (null)

Code:

- (void)parser:(NSXMLParser *)parser didStartElement:(NSString *)elementName namespaceURI:(NSString *)namespaceURI qualifiedName:(NSString *)qualifiedName attributes:(NSDictionary *)attributeDict {
    if([elementName isEqualToString:@"photoset"]) {
        NSMutableDictionary *curInfo = [[NSMutableDictionary alloc] init];
        [curInfo setValue:[attributeDict objectForKey:@"primary"] forKey:@"thumb-id"];
        [setData insertObject:curInfo atIndex:parsedItems]; 
        [curInfo release];
        parsedItems++;
    }
}

When I create curInfo and set the object for the thumb-id key and NSLog() it, I get the expected result. However, when I add that dictionary to the array, then NSLog() that index of the array, it returns (null)

Why would adding a simple object to an array not work? What am I missing?