Неопознанная ошибка при выполнении запроса

void __fastcall TForm1::FormCreate(TObject *Sender)
{
        ADOConnection1->ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" +
        ExtractFilePath (Application->ExeName) +
        "BDkoa.accdb;Persist Security Info=False";
        ADOConnection1->Connected=true;
        ADOQuery1->Active=true;
        Poisk->Active=true;
}

void __fastcall TForm1::ComboBox1Select(TObject *Sender)
{
    String str = ComboBox1->Text, lvl, naim;
    int pos = 1, lenFio = str.Length();
    for(int i = 1; str[i]!=' '; i++)
    {
        lvl += str[i];
        pos++;
    }
    pos++;
    for (int i = pos; i!=lenFio+1; i++)
    {
        naim += str[i];
    }
    Edit4->Text=naim;
    Form1->Poisk->Close();
    Form1->Poisk->SQL->Clear();
    Form1->Poisk->SQL->Text="SELECT * FROM Harac WHERE Level=:zn AND NameS=:naim";
    Form1->Poisk->Parameters->ParamByName("zn")->Value = StrToInt(lvl);
    Form1->Poisk->Parameters->ParamByName("naim")->Value = naim;
    Form1->Poisk->Open();
}

Form1->Poisk->SQL->Text="SELECT * FROM Harac WHERE (Level=:zn) AND (NameS=:naim)";
Form1->Poisk->Parameters->ParamByName("zn")->Value = StrToInt(lvl);
Form1->Poisk->Parameters->ParamByName("naim")->Value = QuotedStr(naim);