[shitbird]

Try this. Untested. Let me know if it returns any errors.

pawn Код:

CMD:b(playerid, params[])
{
    new
        str[128];
        
    if (!strlen(params[0])) {
        SendClientMessage(playerid, -1, "Error: parameter is missing.");
    }
    
    else
    {
        if(AdminDuty[playerid])
        {
            switch(PlayerInfo[playerid][pAdmin])
            {
                case 0: format(str, sizeof(string), "%s %s says: (( %s ))", Accent[playerid], PlayerNameEx(playerid), params[0]);
                case 1: format(str, sizeof(string), "<Mod> %s %s says: (( %s ))", Accent[playerid], PlayerNameEx(playerid), params[0]);
                case 2: format(str, sizeof(string), "<Admin> %s %s says: (( %s ))", Accent[playerid], PlayerNameEx(playerid), params[0]);
            }
        }
        ProxDetector(20.0, playerid, str, COLOR_FADE1,COLOR_FADE2,COLOR_FADE3,COLOR_FADE4,COLOR_FADE5);
        printf("%s", str);
    }
    return 1;
}

You don't need to use sscanf when dealing with one parameter only.
Are you running the latest updated version of sscanf also?