Could Not Start Process 'iw4mp_ceg.exe' Multiplayer Issue

As the topic says, a friend of mine has this very interesting problem which we are unable to resolve, she bought the game today, installed it, tried to go into the Multiplayer part of the game and this is what happes

Could Not Start Process 'iw4mp_ceg.exe' Multiplayer Issue

She's unable to play because of a problem i don't know where it comes from or what to do to fix it..
it would be very kind if someone could help us!