I guess you are using TD Ameritrade They started this practice while BIEL were Caveat Emptor on Pinksheets.com and haven't changed their minds due to the transfer agent, yet many other stocks they do deal with using same agent!
The inability to buy with em means I still have some in my IRA I wanted to sell and buy back cheaper (bought around 0.08 I think) as FDA clearance will give a 0.10 price immediately overnight that I don't want to miss.
I have an Etrade account that trades no problem and have amassed a sizable number of shares at under 1.5c each by buying $300-$500 a month.
TDA have no real excuse, but I am sure if BIEL got off the pink sheets and onto the OTC BB proper they would change their minds.