[Dan.]

FIXED. Problem was in fixes.inc file which was from 2012.

[Lordzy]

Set your "PlayerZoneTimer" array's default value to be -1. While setting it, if it's not equal to -1 (which means it's already active), don't call the timer. Timers can be repeating in case if duplicates are created.

pawn Код:

if(mytimer == -1) 
    SetTimer(...); //else I'm not setting the timer.

[notime]

I myself never used KillTimer because I dont trust it. I've noticed in the past that it doesnt always work. It's a known bug and after 8 years I'm very dissapointed to hear its still not fixed.
How I used to do it is set a variable in the callback of the timer and keep setting the timer over and over again. Once the variable isnt 1 anymore it wouldnt set the timer anymore. If that makes sense to you?

So basically:

pawn Код:

new TimerVar;

Ofcourse you can make it player bound aswel with [MAX_PLAYERS], in that case you have to use SetTimerEx to get the playerid.
Basically at the spot you set the timer dont forget to set the TimerVar(so when he enters the zone):

pawn Код:

SetTimer("GangCount", 1000, false, "iis", playerid, checkpointid, zonename);
TimerVar = 1;

Then your stuff(im not gonna fully copy and paste it though):

pawn Код:

forward GangCount(playerid, checkpointid, zonename);
public GangCount(playerid, checkpointid, zonename)
{
   If TimerVar == 1
   {
      SetTimer("GangCount", 1000, false, "iis", playerid, checkpointid, zonename);
   }
   Your stuff here
}

Then at the spot you placed KillTimer, simply Set the TimerVar = 0; and it stops the timer.