How to get the pubDate tag in a RSS feed

Hi, i want to read a RSS feeds with my iPhone application. Now, i can read all tags without problems, but when i try to read de pubdate tag my variable is null.

NSString *title = [item objectForKey:@"title"];
titleText.text=title;
NSString *description = [item objectForKey:@"description"];
descriptionText.text=description;

The title and description are OK, but when i try this:

NSDate *date = [item objectForKey:@"pubDate"];
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:@"EEEE MMMM d, YYYY"];
NSString *dateString = [dateFormat stringFromDate:date];
dateText.text=dateString;

the TextView dateText is empty. Somebody can help me? Thanks!