Fall to dead causes server crash

[Ni3ls]

Hi all,

Im working on a zombie mod with saving. Everything loads and saves perfectly. However, if I fall to dead (jump from a too high object) the server crashes and says my values are undefined. I can kill, get killed, do suicide, the mod works perfectly. But when I fall to dead it says thats it undefined. And not 1 thing, but all.

		checkachievements()
{
    if(self.rank >= 1 && self.rank5ach==0 )
    {
        text=&"BEGINNER";
        self thread add_achievement(text);
        self.rank5ach=1;
    }

    if(self.rank >= 20 && self.rank20ach==0 )
    {
        text=&"ZOMBIDICAL MANIAC";
        self thread add_achievement(text);
        self.rank20ach=1;
    }
} 
	

I got a hud that shows the correct rank. I also get the message when I get the achievement. It's called from Callback_Playerkilled();
But when I fall to death, it says

pair 'undefined' and '1' has unmatching types 'undefined' and 'int'

But it works because I got the message when I reach rank 1. Who can help me?