This is a common MtGox experience.  I believe it's also why the BTC/USD rate is inflated there relative to other exchanges: people resorting to buying back BTC after they failed to withdraw USD!

For the record though, some people do manage to withdraw their USD, including (eventually) me.  I gather there are some banks they have more trouble withdrawing to than others, including Citibank - unfortunately one of the most common intermediaries in transfers from Japan.  Not very reassuring.  I too wish the best of luck to Bitstamp, had only good experience with them so far.

Jacob