IB API request historical data problem

[APItrader]

Hello

I am using the IB API.

I am trying to request historical data for MSFT and CSCO. Both are in the NASDAQ exchange.

In the below example. The lines where I have declared "SMART". Here it works.
But why doesn´t it work for either MSFT or CSCO when I declare the "NASDAQ" as the exchange?:


//This works
Tws1.reqHistoricalData(0, "MSFT", "STK", "", 0, "", "", "SMART", "USD", 0, "20110505 17:05:00", seconds, "1 min", "TRADES", 1, 1);


//Why does not this work?
Tws1.reqHistoricalData(0, "MSFT", "STK", "", 0, "", "", "NASDAQ", "USD", 0, "20110505 17:05:00", seconds, "1 min", "TRADES", 1, 1);


//This works
Tws1.reqHistoricalData(0, "CSCO", "STK", "", 0, "", "", "SMART", "USD", 0, "20101015 17:05:00", seconds, "1 min", "TRADES", 1, 1);



//Why does not this work?
Tws1.reqHistoricalData(0, "CSCO", "STK", "", 0, "", "", "NASDAQ", "USD", 0, "20101015 17:05:00", seconds, "1 min", "TRADES", 1, 1);