I get the following error when trying to update historical data:
Error retrieving bars:IB error/warning! id=0 200:No security definition has been found for the request
TWS is up and running. I also downloaded the API (http://individuals.interactivebrokers.com/en/p.php?f=programInterface&ib_entity=llc).
In the TWS options (Configure->API) the following is checked "Enable ActiveX and Socket Clients".