[Ryz]

Deathmatchon[playerid] = false;

do it

EDIT:

sorry

change

pawn Код:

new Deathmatchon[MAX_PLAYERS];

to

pawn Код:

new Deathmatchon;

and correct

pawn Код:

public OnPlayerPickUpPickup(playerid, pickupid)
{
    if(pickupid == DeathMatch)
    {
       if (Deathmatchon == true)
       {
           SendClientMessage(playerid, -1, "There is already a death match on!");
       }
       else if (Deathmatchon == false)
       {
           ShowPlayerDialog(playerid, Deathmatch, DIALOG_STYLE_LIST, "DeathMatch list", "LS carpark DM\nLV warehouse DM\nSF tennis courts" , "Yes", "No"); // Add more if you want!
       }
    }
    return 1;
}