Lazarus emit error "External SIGSEGV"

[kanok rojjanakitti]

my pascal code
normal structure programming
var ta:array[1..8,1..8]of byte;
procedure fillArray;
var r,c,n:byte;
begin
n:=0;
for r:= 1 to 8 do
for c:=1 to 8 do
begin ta[r,c]:=n;n:=n+1;end;
end;
It's works on Lazarus Simple program
numO=Object
procedure numO.fillArray;
var r,c,n:byte;
begin
n:=0;
for r:= 1 to 8 do
for c:=1 to 8 do
begin ta[r,c]:=n;n:=n+1;end;
end;
It's works on TPW 1.5 for window program
numC=class
procedure numC.fillArray;
var r,c,n:byte;
begin
n:=0;
for r:= 1 to 8 do
for c:=1 to 8 do
begin ta[r,c]:=n;n:=n+1;end;
end;
not work in Lazarus and it emits message" External SIGSEGV" at
ta[r,c]:=n;n:=n+1;