Urgent help required

Dear Sirs/Mams, We are a Kraft Paper Manufacturing Co., We purchased some input from a dealer during fy 2011, say 14.07.2011. but respective entry could not be passed due to some disputes. Can we pass purchase entry on 01.04.2012? Can we take Cenvat credit of excise duty paid on such purchases during May'2013. Kindly revert back. Regards, Lalit Dhabria