Access Violation at module project1.exe

i have a problem to this code :

Form1->ADOQuery2->SQL->Clear();
Form1->ADOQuery2->SQL->Add("SELECT * FROM setting WHERE item = 'use'");
Form1->ADOQuery2->Open();
String use = Form1->ADOQuery2->FieldByName("color")->AsString;
if(use == "1")
  cbKupon->Checked = true;
else
  cbKupon->Checked = false;

i get error "access violation at module project1.e x e" when i try to checked/unchecked checkbox based value of 'use'

How to fix it ?