"Unable to confirm order" Error

Test system 77464959 gets the error "Unable to confirm order" or the pending Futures Limit Order just disappears some time after entry. This is happening with limit orders that should be filled. At 20:40 EDT on 3/17/13 I get the following message on the trade blotter: "@YMM3 is MINI DOW [CBOT Chicago Board Of Trade] (futures) - Delayed Price: 14318.00" (when starting a new order ticket) while I have a buy to open limit order pending at 14320.00 that is parked with the "Unable to confirm order" error and the spinning arrows showing it is "working".

The problem is you are entering your order as "Sell To Close" but you have no open position. Try Selling Short.

The "Sell To Close" that you see was cancelled prior to this error and forum post. The cancelled "Sell To Close" arose due to C2 being "out of sync" with TradeStation which reported fills on limit orders for @ESM3 - buy to open on limit at 1538.75 and @YMM3 - buy to open on limit at 14320. These were both filled in TradeStation while they are still pending with "Unable to confirm order" on C2. I would attach a screen shot if that was possible.

The "Sell To Close" was only entered because the C2 and TradeStation systems are out of sync. It is because the systems are out of sync that I am manually entering (without success) the limit orders on the system trade blotter page.

Can you please tell me what would cause my entry orders to disappear or be pending with the "Unable to confirm order" dialog when the format appears correct? Can it be related to quote feed delays or errors? Is there anything else that can cause the error? I just want to understand what is going on here so I can deal with it. Thanks!