Still no response from email or twitter.
This is very sketchy. What right do they have to freeze a pure BTC account?
It's not that BTC funds have been frozen; it's that most weren't being held online (i.e. in a hot wallet). After a system breach and massive theft of all users' bitcoins last year, bitfloor took the correct security measure of storing most user BTC funds offline (i.e. in a cold wallet).
Obviously with bitfloor shutting down operations, there's been a run of users all trying to withdraw funds. After the hot wallet is exhausted, BTC withdrawals can no longer be completed automatically on bitfloor's servers. It requires manual action in order to process the transaction. Such is the inconvenience of using a cold wallet as security precaution, and so your withdrawal will remain in the "pending" state until you can get someone to manually enact it for you -- assuming, of course, that your funds are indeed available and being stored in bitfloor's cold wallet.