[XStormiest]

Is not that good, also you did some mistakes
If you type this:

pawn Code:

SetTimer("agate", 15000, 0); //timer for 15 sec

, that means this timer function doesn't have any parameter:
you should do:

pawn Code:

SetTimerEx("agate", 15000, 0, "i", playerid);

Anyway 1/5 for the tutorial:
- Mistakes ( - 2 p )
- Not Good Explained ( - 2p)