This has to do with penny stocks in general and clearing house issues. Anything under a certain price, can't recall what, and some firms won't let you trade it. Zecco is one.
Scottrade allows you to trade it as does, as was mentioned, TDAmeritrade and many others but there are a few that have limited penny stock trading and/or place price and other restrictions and only allow you to trade certain ones that meet their criteria.
All this happened about 8 months or so ago. Forget the particulars frankly as it didnt affect what was doing.