PowerPivot and PowerView in SharePoint 2013

Hello 

I have created two servers(Server A and Server B). Server A is application server which I've installed SharePoint 2013 and Server B is the machine which I've installed SQL Server 2012SP1. 

I've created My SharePoint and added BI features. SSRS reports works without problem. It works in Wep Parts or in the galleries. However, I've problem with PowerPivot and Powerviews. When I deploy a PowerView and PowerPivot then I cannot open them. Every time it gives me the permission errors. It says something like you don't have permission in every time. But, I am the DB_Owner of the database. There shouldn't be a permission error. That I cannot understand. Please explain me. 

Thanks in advance..