Call procedure

[question]

Code:

Unit1 
public
procedure Add(Sender: Tobject)
......
Procedure TFrom1.ADD(Sender:Tobject);
begin
....
end;


Unit2
Procedure Done(Sender:Tobject);

uses
  unit1;

var
 TTest : TForm1;

Procedure TFrom2.Done(Sender:Tobject);
begin
TTest.Add(Sender);
end;

i get the error "Zugriffsverletzung bei Adresse 00C683D7 in Modul 'test.exe'. Lesen von Adresse 00000028."
i have also tried with TTest,create(nil); but i always get this error message, how can i overcome it?