Uable format field

I get the following error trying to auto-trade signals from Collective2 trough Trader68 at Interactive Brokers:

Warning 06/29/2010 11:54:00 AM IB/TWS: IB: Error reading request:-‘xb’ : cause - Unable format field - (IB #320, Order #38588)

Info 06/29/2010 11:54:00 AM My Collective2 Portfolio: TF: TFU0: Generated Order to Buy 1 at Stop 624.1 (Enter Long (from Collective2# 50673529))

What is causing this error and how can it be fixed?

Thank you,