Storyboard moving Image animation crashed app

I am developing app for Windows phone-8 and using pivot control I want to move background Image of pivot control using story board and loading data in Longlistselector with in pivot control.app crashes after 5-6 iteration and shows up me error____The program '[2012] TaskHost.exe' has exited with code -2147220978 (0x8004020e).

I am using this code to move backgroung Image of pivot control while moving item of Pivot control..