title: NSData dataWithContentsOfURL issue
body: <p>I have a string with url.Please take a look at the following code.I am not getting what's the error.Getting an exception like :</p>
  
  <h2>Exception :</h2>
  
  <pre><code>[NSCFString isFileURL]: unrecognized selector sent to instance 0x4b69700
  2011-04-22 00:16:30.520 SC.Pandit[15098:207] *** Terminating app due to uncaught           
  
  exception 'NSInvalidArgumentException', reason: '-[NSCFString isFileURL]: unrecognized selector sent to instance 0x4b69700'
  </code></pre>
  
  <h2>My Code :</h2>
  
  <pre><code>NSURL *url =(NSURL *) imageURL;
  NSLog(@"%@",url);
  NSData *data = [NSData dataWithContentsOfURL:url];
  </code></pre>