Fidelity will let you buy pink sheets, but I've seen this before.
It happened to me 4-6 weeks before AND! ran big time. I use Ameritrade and they wouldn't let me buy that one at that time. About a month later it ran.
I have seen other brokerages do the came thing about a month or so before a run. Its like they run out of the shares that they have available or something.
I have since opened an account with E Trade in addition to my Ameritrade account for that reason.