Some people i know are having problems where if you go to hit the bid, instead of getting filled at bid you would offer out one penny above instead, and then lower to the former bid price once it disappears. Anyone else see this problem?
Sounds like the s/w thinks you're trying to short. Maybe it was a mistake, trying to sell a stock that you weren't long or a custom key is mismapped.
New downtick rule went into affect for short selling stocks that are down >10% (effective Feb 28th) http://www.sec.gov/rules/final/2010/34-63247.pdf