You do NOT need to enable DDE API on the TWS API settings. In order for MT to work, you just need to enable the topmost checkbox - "Enable ActiveX and Socket Clients". Also, strongly suggested that you add the Trusted IP Address (bottom of that setting screen). Assuming you are running TWS on the same computer as MT, you would click CREATE and enter 127.0.0.1 as the IP address. click OK and try connecting with MT again. As for subscriptions, delayed data is NOT enough for getting intraday backfill and quotes. You have to have real-time for that. I do not know about Historical data. However, if you are just getting Historical charts for US Equities or other securities supported by google and Yahoo, you can just use those sources in MT for "Historical Backfill" instead of IB.