Yesterday on the open I submitted a batch of orders to IB (using IB API connected to Excel DDE spreadsheet) and nothing happened. No status update, no submission....nothing. I hit submit a few more times, and finally they went through. Unfortunately, by this time the market had already been open for 3 minutes so many of the trades took off without me being onboard. Incredibly frustrating.
Lots of glitches at IB....if I knew of a reputable broker who provided an API for order submission and had low commission trading I'd probably consider switching at this point.