Why the page launch cannot be started when a reminder is displayed

I used the sample code below for testing. I couldn't figure out what went wrong. Please rate if you can point out what I need to do when setting up or using the reminder.

1) ShowParams.xaml is configured

2) Below is the code to add a reminder:

Uri navigationUri = new Uri ("/ ShowParams.xaml" + queryString, UriKind.Relative);

            Reminder reminder = new Reminder (name);
            reminder.Title = titleTextBox.Text;
            reminder.Content = contentTextBox.Text;
            reminder.BeginTime = beginTime;
            reminder.ExpirationTime = expirationTime;
            reminder.RecurrenceType = recurrence;

            reminder.NavigationUri = navigationUri;

            // Register the reminder with the system.

            ScheduledActionService.Add (reminder);

thank