I want take screenshot on my phone and I managed successfully get one screenshot (Back button + Home) but when I tried again, there isn't any camera shatter sound

somebody help me?

Yeah, I forget to write that I'm using Samsung Galaxy Ace. My phone isn't rooted yet, I just let it be ^^;;

Ah I see. I once successfully screen capture but it's only once. So that's mean I have to find apps to screenshot. Thanks anyway =)