interbase_db = new TIBDatabase (this);
   interbase_db->LoginPrompt = false;
   ib_table = new TIBTable (this);
   ib_table->Database = interbase_db;
   ib_sql = new TIBSQL (this);
   ib_sql->Database = interbase_db;
   ib_transaction = new TIBTransaction (this);
   ib_sql->Transaction = ib_transaction;
   ib_table->Transaction = ib_transaction;
   interbase_db->DefaultTransaction = ib_transaction;
 все здесь путем

  interbase_db->DatabaseName = fName;
  interbase_db->SQLDialect =  3 ;
  interbase_db->Params->Clear ();
  interbase_db->Params->Add("user_name="+ UserName );
  interbase_db->Params->Add("password=" +UserPassword);
  interbase_db->Params->Add("lc_ctype=WIN1251");
  interbase_db->Open ();
  ib_transaction->Active = true;
 и здесь все путем

 И наконец когда я пытаюсь открыть таблицу
  ib_table->Active = false;
  ib_table->TableName = tabNameTo;
  ib_table->Active = true;