[Garr]

Код:

enum pStats{
	Killstreak
}
new Player[MAX_PLAYERS][pStats];

Код:

public OnPlayerDeath(playerid, killerid, reason)
{
 	Player[playerid][Killstreak] = 0;
	return 1;
}

Call the name of the array when you want to change something in the enum, not the enum's name itself. Player[playerid][thingtobeset]