couldn't close or click on invite a friend windows & sometimes i had Error: 15

sometimes Game Error: 15 shown when i want to launch the game, in addition also when i open the game and try to accept an invitation or open invite a friend windows, it just appear and i couldn't press any bottom in it, or even close it, and it will not close until i Exit from the game.

please advice


@ NWI: the beta is no longer around, this forum should be closed for new posts (and possibly archived)

@Hamdi please ask the moderators to move this topic to the correct forum.