Battle net support errormessages

Whenever I click on battle.net it pops up an error window. I've tried everything that I were able to do from battle.net/support and I've reinstalled numerous of times. Have anyone else encountered this problem and managed to fix it? This happens on both live and Slash Diablo gateway. Here is what it says: "UNABLE TO CONNECT" Unable to connect to battle.net If using a modem, you may need to connect your internet service provider before connecting to battle.net. For more informatrion, please.