Among the many, many things that MtGOX's press release did not explain:
* When did the BTC withdrawal bug start happening?
* If the bug was alway there, why didn't it cause problems years ago?
* If the bug is recent, why did they replace a validation code that worked by that buggy one?
* Clients have been complaining for months about the errors. Why wasn't the bug found and fixed before?
They could also have at least stated (even without showing evidence) the basic numbers of their financial position:
* how many bitcoins they have in their wallets and how much money they have in the bank;
* how many bitcoins and how much money they owe to their clients (ie. the sum of balances of all accounts);
* how many bitcoins and how much money clients have asked to withdraw but have not been allowed to.
The answer to the last question seems to be in the tens of millions of dollars at least.
I take their unwillingness to give these basic numebrs as strong evidence that they are insolvent.