[Lazarus] Problem growing an array

[appjaws]

Hi,
Could one of you experts look at my code please.
My program crashes after the first set of strings are added because -- I 
think -- the length is not updating.
The following is just a snipet.
type
    Detail = record
      Extra1, Extra2, Extra3, Extra4, Extra5, Extra6, Extra7, Extra8 :string
    end;

var
   Form1: TForm1;
   head : array [0..7] of string = ('Extra1', 'Extra2', 'Extra3', 
'Extra4','Extra5', 'Extra6', 'Extra7', 'Extra8');
   x : integer;
   y : integer;
   z : integer;
   w : integer;
   currentLength : integer;
   collection : array of Detail;
   information : array  of array of string;

procedure TForm1.MenuItemInputClick(Sender: TObject);
//initial setup
begin
      SetLength(collection,1);
      SetLength(information,8,1);
end;

procedure TForm1.ButtonNextClick(Sender: TObject);
begin
  // extend array lengths
        if Length(collection) < (y+1)then
        begin
        SetLength(collection, y+1);
        SetLength(information[x],y+1);
        end;

  // load array
        information[0,y] := TEdit1.Text;
        information[1,y] := TEdit2.Text;
        information[2,y] := TEdit3.Text;
        information[3,y] := TEdit4.Text;
        information[4,y] := TEdit5.Text;
        information[5,y] := TEdit6.Text;
        information[6,y] := TEdit7.Text;
        information[7,y] := TEdit8.Text;

//display aray lenghts
        z := (Length(collection));
        LabelResult.Caption := inttostr(z);
        w := (Length(information));
        LabelResult1.Caption := inttostr(w);
  //write to listbox
        for  x := 0 to 7 do
          begin
          ListBox1.Items.Add(head[x] + ' ' + information[x,y] + ' ');
          end;
   //clear edit boxes
        TEdit1.Text := ' ';
        TEdit2.Text := ' ';
        TEdit3.Text := ' ';
        TEdit4.Text := ' ';
        TEdit5.Text := ' ';
        TEdit6.Text := ' ';
        TEdit7.Text := ' ';
        TEdit8.Text := ' ';
        y := y + 1
end;

After the first set of strings are added, I get this error message:-

Project protection raised exception class 'External: SIGSEGV'.

I'm sure it's just me not understanding how arrays should be manipulated,
Look forward to any help
Paul
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