Occuring error as : Index (zero based) must be greater than or equal to zero and less than the size of the argument list.

Am using this code to fetch Name, Username, Password from Database.

List<string> lst = new List<string>();
        lst = ctrl.retrive_email(email);
        foreach(string value in lst)    
        {
            name=string.Format("{0}",value);
            uname = string.Format("{1}", value);
            pwd = string.Format("{3}", value);
        }

But getting an Error as ::  Index (zero based) must be greater than or equal to zero and less than the size of the argument list.