Fatal G2 error

Here's the error from G2: Error (ERROR_PERMISSION_DENIED) : Invalid return URL! The requested URL http://piksel.no/wpg2/?g2_controller=cart.AddToCart&g2_itemId=257&g2_return=%2Fwpg2%3Fg2_itemId%3D257%26g2_page%3D3%26g2_wpg2_returnurl%3Dhttp%253A%252F%252Fwww.piksel.no%26g2_wpg2_returnname%3DPIKSEL&g2_returnName=album tried to insert a redirection to /wpg2?g2_itemId=257&g2_page=3&g2_wpg2_returnurl=http%3A%2F%2Fwww.piksel.no&g2_wpg2_returnname=PIKSEL which is not a part of this Gallery.