[Deduction]

It cant be in that code because the error says String and there is no string with a capital in that. So locate the String with the capital and replace it with lowercase letters. aka string

Here it is:

Use this command.

pawn Код:

CMD:e(playerid, params[])
{
    new tekst[128], string[128], id;
    new Float:x, Float:y, Float:z;
    if(PlayerInfo[playerid][pAdmin] < 1)return SendClientMessage(playerid, COLOR_WHITE, "Niste ovlasteni");
    else if(sscanf(params, "s[128]", tekst))return SendClientMessage(playerid, COLOR_WHITE, "/e [Tekst]");
    GetPlayerPos(playerid, x, y, z);
    format(string, sizeof(string), "(( Admin %s: %s ))", PlayerName(playerid), tekst);
    ProxDetector(50.0, playerid, string, -1);
    return 1;
}