[vIBIENNYx]

Found the problem, add this:

pawn Код:

forward ClassTimerInvin(playerid);
public ClassTimerInvin(playerid)
{
    ClassSelectedInvin[playerid] = 0;
     IsInvincible[playerid] = 1 // <-----
    KillTimer(ClassTimerInvinVar);
    return 1;
}
forward Invincible(playerid);
public Invincible(playerid)
{
    if(IsInvincible[playerid] == 0) return IsInvincible[playerid] = 1;
    SetPlayerHealth(playerid,50);
    SendClientMessage(playerid,-1,"You are now Un-Invincible");
    return 1;