My vehicle is fitted with the Nissan connect premium audio system that has a Hard drive Sat Nav system. It works great but is very out of date. Via a Nissan dealership I obtained a Navteq 2011 DVD update however when I try to instal it comes up with an unreadable message. Nissan cannot help or wont help and the dealership is likewise clueless. I understand this is a problem but surely there is a solution. The disc I have is a genuine supply and although I didn't have to pay these retail as circa £170. Advice welcome please