[AndreT]

Okay that is just PLAIN HORRIBLE.

You should definitely not use PVars in OnPlayerUpdate. And actually you don't even need GetTickCount().

What you should do to detect AFKing is:
1. in OnPlayerUpdate, keep setting a variable to 0
2. in your 1-second timer, keep incrementing the variable until it reaches 2. If it reaches 2, the player is not sending updates anymore (is paused, about to time out, whatever)

pawn Код:

new updating[MAX_PLAYERS char];

public OnGameModeInit()
{
    SetTimer("checkAFK", 1000, true);
}

public OnPlayerUpdate(playerid)
{
    updating{playerid} = 0;
}

forward checkAFK();
public checkAFK()
{
    foreach(Player, i)
    {
        if(updating{i} < 2)
            updating{i} ++;
        else
        {
            // Player went AFK!
        }
    }
}

Basic but you get the idea.