If it takes 10 minutes to find your position, the phone is not using A-GPS, but just relying on GPS signals. Do you have A-GPS enabled in GPS settings (there are two options in GPS settings, turn both of them on)? Do you have a sim-card inserted in your phone? And do you have an active internet connection?

Also, grab the GPS Meefo app from the store to check how many satellites can your phone "see" when you encounter trouble - http://store.ovi.com/content/200444