Last weekend I bought some things at home depot so that I could mount on the wall of my room a pair of speakers I just bought. So I did the measuring to keep the speakers at an equal distances, prepared to drill the wall, everything appeared to be going fine, I drilled exactly 5cm as the manual said. But then when I put the plastic things where the screws go, they didnt go all the way in, so i sort of forced the screw and I ended up cracking the wall an a small part of the paint fell down, .

No I am going to have to look for another place to hang my speakers and get somebody to fix my wall. I will investigate on how I can do it myself.

You might be able to 'repair' the holes with drywall anchors.
There are some "threaded" drywall plugs which should be strong enough to hold speakers.
Visit a local hardware store, tell them your problem and they should be able to fix you up.
The ones I am thinking of cost about 50 cents each and need a starter hole, then you simply screw the speakers to them.

Yeah, I will go to the hardware store tomorrow. Thats going to be my first priority. Ill post before and after pictures just for the curious. Thanks for the support jlhaslip.