Das ist ja auch kein Wunder...
Hatte dich gefragt gehabt, wie du playerteamname definiert hast...
stock playerteamname(playerid)
{
new teamRankName[30], string[128];
GetPlayerName(playerid,string,MAX_PLAYER_NAME);
switch(spielerinfo[playerid][pAdmin]){
case 0:{teamRankName = "Spieler";}
case 1:{teamRankName = "Supporter";}
case 2:{teamRankName = "Supporter";}
case 3:{teamRankName = "Moderator";}
case 4:{teamRankName = "Moderator";}
case 5..1337:{teamRankName = "Administrator";}
case 1338:{teamRankName = "Server Managment";}
return teamRankName;
}