Filing itr for ay 2011-12

Hi,

My client has received an IT notice for filing the returns for the AY 2011-12 since he has not filed the ITR for this AY. I filled up the utility spread sheet for this year under '139(4)'. Now while uploading the XML file generated by the utility, the system is not accepting the file. I am getting a message as "The end date for filing the ITR is over."  How  should I proceed with efiling the return for this AY? Please advise...