Why does my nav still have me driving in the ocean?

I bought an updated disc because my nav suddenly had me driving out in the ocean, but it hasn't changed a thing. What's wrong? Who do I take it to in order to fix it? I bought the car used. The car is a 2000 Mercedes ML320.
CJ, December 2007
Did you buy PIRATE software?

Nala, February 2008
Your satnav thinks it is on a boat! You will need to change the software and/or settings.

Colin, December 2007
link Click here to see other fixes for Mercedes.