My guess would be that he borrowed money from GLBSE, exchanged it to fiat and now that BTC prices have rised, he doesn't have enough money to buy bitcoins to pay back.
If this is the reason he should come clean and ask if people would be willing to take their payment in the USD equivalent of when he shut down. I know I would. I would rather have something than nothing.
But he knows we won't do anything about it so we are all hosed.