Changing slider value of custom transport control gives an exception {"Value does not fall within the expected range."}

Changing slider value of custom transport control gives an exception
{"Value does not fall within the expected range."}

With the sample app:
http://code.msdn.microsoft.com/windowsapps/Basic-Media-Playback-003619be#content
Custom transport control is not working. Moving slider thumb gives an
exception:
BasicMediaPlayback.exe!SDKTemplate.App.InitializeComponent.AnonymousMethod__9(object
sender, Windows.UI.Xaml.UnhandledExceptionEventArgs e) Line 50 C#
with no other call stack entries.
I also tried putting
await Task.Delay(500);
and stopping timer before actually updating the timeslider value or
mediaelemnet position but still getting same exception. The problem is,
control is not even going to the event handler. I get same exception even
if I remove the evenhandlers attached in code behind.
do I need to set anything before running this scenario? Am I missing
something? please help.