title: iOS Swift - UITableView didselectrowatindexpath crashes
body: <p>First of all, let me say that this is a noobish question so please bear with me here :D. I have a tableview embedded in a navigation control and it is my main view. There is an "Add" button where I can add "things" then when that is triggered it shows the added item on the table view and also switches back to the main view controller with the code below</p>
  
  <pre><code>@IBAction func buttonAddPost_Click(sender: UIButton) {
  postMgr.addPost(titleBox.text, description: descriptionBox.text, postDate: date)
  self.navigationController.popToRootViewControllerAnimated(true)
  }
  </code></pre>
  
  <p>Again the above code takes me back to the main table view controller just fine.</p>
  
  <p>But when I click on a cell to take me to a more detailed view, the app crashes. Here is the code</p>
  
  <pre><code>override func tableView(tableView: UITableView!, didSelectRowAtIndexPath indexPath: NSIndexPath!) {
  let listingPage = self.storyboard.instantiateViewControllerIdentifier("listingPage") as PostListingTableViewController
  self.navigationController.pushViewController(listingPage, animated: true)
  }
  </code></pre>
  
  <p>"listingPage" is the storyboard ID for the new view controller I'm trying to go to. I have used the above technique a few times somewhere else and worked just fine but I'm not sure what's wrong here.</p>
  
  <p>Error I get:
  Thread 1
  0  swift_dynamicCast and it highlights 0x1d7150: pushl %ebp     Thread 1: EXC_BREAKPOINT (code=EXC_I386_BPT)
  1
  2 Exchange.PostlistTableViewController ([app name].[class name]) and it highlights the didselectrowatindexpath
  .
  .
  .</p>
  
  <p>Please help...</p>
  
  <p>KM</p>