Dear All,

I thought of setting-up this topic ...so that expert gamers can help out novice gamer...on gameplay, strategies,..etc.

Actually I'm stuck in playing the Game on PS3.
I'm at this stage on a rooftop (in a typical American town) surrounded by Armored Cars and Enemy fires. I picked up a STINGER Rocket launcher to destroy the Armored Cars...(by aiming L1 and press R1 the fire button on the target). But that damn STINGER pops up a message that says "Lock On Required". I pressed all the buttons but can't acquire "lock-on". What-the-f***'s wrong? This modern weapon is puzzling.
Can anyone help? Thanks.