I've linked output from the IB to the code, as shown below.
class DiaryTableViewCell: UITableViewCell {
    @IBOutlet weak var TitleLabel: UILabel!
    @IBOutlet weak var SubTitleLabel: UILabel!
    @IBOutlet weak var leftImageView: UIImageView!
    @IBOutlet weak var rightImageView: UIImageView!
}
Here, I'm registering the class:
override func viewDidLoad() {
   self.title = "My Diary"
   cellNib = UINib(nibName: "TableViewCells", bundle: nil)
   tableView.registerClass(DiaryTableViewCell.classForCoder(), forCellReuseIdentifier: kCellIdentifier)
}
 

But I keep getting the following runtime error:
*** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '...setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key SubTitleLabel.'
From within the following code: 
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell = tableView.dequeueReusableCellWithIdentifier(kCellIdentifier) as DiaryTableViewCell?
if (cell == nil) {
    tableView.registerClass(DiaryTableViewCell.classForCoder(), forCellReuseIdentifier: kCellIdentifier)
    cell = cellNib?.instantiateWithOwner(self, options: nil)[0] as? DiaryTableViewCell
                cell?.selectionStyle = .None
}
if (cell != nil) {
    println("\(x++)) Inside cell")
    cell!.TitleLabel.text = "Hello"
    cell!.SubTitleLabel.text = "World"
}
return cell!
}
Specifically, it's happening here: 
cell = cellNib?.instantiateWithOwner(self, options: nil)[0] as? DiaryTableViewCell
Question: How am I violating the key value coding-compliant for a UILabel?
This hasn't happened before... UILabel is KVO compliant.
 
    

 
    
 
     
    