"Нет индексного свойства по умолчанию для типа integer"

type
  TWorkers = Record
    LastName: string[30]; {фамилия}
    Born: integer; {год рождения}
    Experience: integer; {стаж}
  end;
 
var
  i, j, nx, n, g: integer;
  TWorkersList: array[1..20, 1..20] of TWorkers;
 
{=======================================================================================================} 
 
procedure Merge(var TWorkersList, first, last: integer);
var
  middle, start, final, h: integer;
  mas: array[1..20, 1..20] of TWorkers;
begin
  middle := (first + last) div 2;
  start := first;
  final := middle + 1;
  for h := first to last do
    if (start <= middle) and ((final > last) or (TWorkersList[start].Born > TWorkersList[final].Born)) then
    begin
      mas[h] := TWorkersList[start];
      inc(start);
    end
    else
    begin
      mas[h] := TWorkersList[final];
      inc(final);
    end;
  for h := first to last do TWorkersList[h] := mas[h];
end;
 
procedure MergeSort(var TWorkersList, first, last: integer);
begin
  if first < last then
  begin
    MergeSort(TWorkersList, first, (first + last) div 2);
    MergeSort(TWorkersList, (first + last) div 2 + 1, last);
    Merge(TWorkersList, first, last);
  end;
end;
 
{==========================================================================================================}
 
begin
  write('Введите размерность квадратной матрицы: ');readln(nx);
  writeln('==============================================');
  for i := 1 to nx do
  begin
    for j := 1 to nx do
    begin
      write('Фамилия: ');readln(TWorkersList[i, j].LastName);
      write('Год рождения: ');readln(TWorkersList[i, j].Born);
      write('Стаж: ');readln(TWorkersList[i, j].Experience);
      writeln('===========================================');
    end;
  end;
  writeln('============Исходная матрица=============');
  for i := 1 to nx do
  begin
    for j := 1 to nx do
    begin
      writeln('Фамилия: ', TWorkersList[i, j].LastName, ' ', TWorkersList[i, j].Born, ' г.р', ' ', 'Стаж: ', TWorkersList[i, j].Experience, ' лет');
    end;
  end;
  writeln('========================================');
  for j := 1 to nx do MergeSort(TWorkersList, 1, n);
end.

procedure MergeSort(var TWorkersList, first, last: integer);
begin
  if first < last then
  begin
    MergeSort(TWorkersList, first, (first + last) div 2);
    MergeSort(TWorkersList, (first + last) div 2 + 1, last);
    Merge(TWorkersList, first, last);
  end;
end;

type
  TWorkers = Record
    LastName: string[30]; {фамилия}
    Born: integer; {год рождения}
    Experience: integer; {стаж}
  end;
 
var
  i, j, nx, n, g: integer;
  TWorkersList: array[1..40] of TWorkers;//вместо матрицы
 
{=======================================================================================================} 
 
procedure Merge( first, last: integer);//Убрал парметр ,почему?Он мне не понравился)
var
  middle, start, final, h: integer;
  mas: array[1..40] of TWorkers;
begin
  middle := (first + last) div 2;
  start := first;
  final := middle + 1;
  for h := first to last do
    if (start <= middle) and ((final > last) or (TWorkersList[start].Born > TWorkersList[final].Born)) then
    begin
      mas[h] := TWorkersList[start];
      inc(start);
    end
    else
    begin
      mas[h] := TWorkersList[final];
      inc(final);
    end;
  for h := first to last do TWorkersList[h] := mas[h];
end;
 
procedure MergeSort(first, last: integer);//Здесь тоже убрал
begin
  if first < last then
  begin
    MergeSort(first, (first + last) div 2);
    MergeSort( (first + last) div 2 + 1, last);
    Merge(first, last);
  end;
end;
 
{==========================================================================================================}
 
begin
  write('Введите размерность: ');readln(nx);//Размерность == количеству вводимого юзером
  writeln('==============================================');
  for i := 1 to nx do//теперь же обычный массив
    begin
      write('Фамилия: ');readln(TWorkersList[i].LastName);
      write('Год рождения: ');readln(TWorkersList[i].Born);
      write('Стаж: ');readln(TWorkersList[i].Experience);
      writeln('===========================================');
    end;
    
  for j := 1 to nx do MergeSort( 1, n);//Отсортируем прежде чем вывести
  writeln('============Записанное=============');
  var Year:string;
  for i := 1 to nx do
  begin
  IF TWorkersList[i].Experience<4 then Year:=' Год' else Year:=' Лет';//Для красоты)
      writeln('Фамилия: ', TWorkersList[i].LastName, ' ', TWorkersList[i].Born, ' г.р', ' ', 'Стаж: ', TWorkersList[i].Experience,Year);
    end;
  writeln('========================================');
end.