The problem is the same it has been since long before Obama took office; where to put the terrorists if Gitmo closes. That problem did not seem to be a concern to Obama before, but apparently what ever solution he thought he had is now acknowledged as insufficient.
"Nestled among a string of improbable victories President Barack Obama racked up in the lame-duck congressional session is legislation containing the most debilitating setback to date to his plan to close the military prison at Guantanamo Bay and send many of its detainees to trials in civilian courts in the U.S.
Language contained in the 2011 National Defense Authorization Act passed by the House and Senate on Wednesday bars the use of Pentagon funds to transfer any Guantanamo prisoner to the U.S. for any reason, including a trial. Some supporters of plan Obama announced on his first full day in office to close the prison said the passage of the legislation signals nearly complete capitulation by the president."