Well, the tax return should be filed as soon as possible to stop the interest/penalties from accruing. I'm not sure what type of taxes are due estate/trust income (1041)? Estate tax? State taxes of some sort?
If the estate was properly handled and closed for issues other than this it is likely that the estate beneficiaries were asked to sign an indemnification agreement of some sort which basically says you can go back to the beneficiaries and demand there pro-rata share of any debts due that were missed the first time around.
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