destructor - override: memory management(again)

So, this is basically a follow up to another question I posted earlier about memory management.

Consider the following classes:

TCell = class(TObject)
  status : cell_status;
  nA1, nA2 : integer;
  strand: integer;
  to_update : cell_status;
  lifetime: integer;
  resist: integer;
  activated: bool;
  constructor create();
end;

TMargolusBlock = class(TObject)
  cell : array[0..3] of TCell;
  cellCountH, cellCountA1, cellCountA2, cellCountA3, cellCountD : integer;
  LatticeReference1, LatticeReference2 : Integer;
  constructor create(cell0,cell1,cell2,cell3 : TCell);
  //destructor Destroy;
   // override;
end;

TMargolusArray = class(TObject)
  mblock : array of array of TMargolusBlock;
  constructor create(size : Integer);
  destructor Destroy;
    override;
end;

These are the constructors:

constructor TMargolusBlock.create(cell0,cell1,cell2,cell3 : TCell);
begin
  self.cell[0] := cell0;
  self.cell[1] := cell1;
  self.cell[2] := cell2;
  self.cell[3] := cell3;
  self.cellCountH := 0;
  self.cellCountA1 := 0;
  self.cellCountA2 := 0;
  self.cellCountA3 := 0;
  self.cellCountD := 0;
end;

constructor TMargolusArray.create(size : Integer);
begin
  setlength(mblock, size+1, size+1);
end;


Now, I tried using a custom destructor:

When I only use the second one it works(I think, I have some suspicions about memory usage/leakage)
but when I add the first one (Destructor TMargolusblock.Destroy) I get an error
Can anyone explain this to me?

{*
Destructor TMargolusblock.Destroy;
var
  Teller1 : Integer;
begin
    for Teller1 := 0 to 3 do
    begin
      cell[Teller1].Free();
    end;
   inherited destroy;
end;
*}

Destructor TMargolusArray.Destroy;
var
  Teller1, Teller2 : Integer;
begin
    for Teller1 := low(mblock[0]) to high(mblock[0]) do
    begin
      for Teller2 := low(mblock[0]) to high(mblock[0]) do
      begin
        mblock[Teller1, Teller2].Free();
      end;
    end;
   inherited destroy;
end;

This is when using another procedure to fill the MargolusArray.

After some debugging/testing I also noticed that this gives an error(related I guess):

constructor TMargolusArray.create(size : Integer);
var
  Teller1, Teller2 : Integer;
  empty_cell : TCell;
  empty_margolus : TMargolusBlock;
begin
  setlength(mblock, size+1, size+1);

  empty_cell := TCell.create;
  empty_margolus := TMargolusBlock.create(empty_cell,empty_cell,empty_cell,empty_cell);
  for Teller1 := 0 to size do
  begin
    for Teller2 := 0 to size do
    begin
      mblock[Teller1, Teller2] := empty_margolus;
    end;
  end;

Or even:
  mblock[5,5] := empty_margolus;
  mblock[5,6] := empty_margolus;

end;

I thought the mblock[index1,index2] was just a pointer to the empty_margolus memory location..?

Hope someone can explain it to me :)