I beleve they have it set so an order can't be placed more than 50% of the previous closing price. Supposedly so they don't have unrealistic orders in clogging up their system. It is crazy you can't do it especially on biotech stocks that can swing wildly on news. I've read on forums where people haven't been able to sell in afterhours and by the next day had to sell for less than the night before's price.
I guess they don't want Three Finger sell orders on a 30 cent stock.