Credit of advance tax paid not given

Hi everyone..

I need your guidence regarding one issue.one of my CA friend filed return of his client for AY 2008.09 through oversite

he forgot to give credit of 1 st installment of  advancetax  of Rs 40000/-. after that CA friend has filed rectification and claimed advance tax credit now ITO has replied "It came to the notice that you have not claimed advancetax of Rs 40000/- paid on 15.10.2007 in the return of income Hence credit of the said advance tax cannot be allowed while passing the rectification order"

so Incometax act will not allowed assessee to claim credit of advance tax paid which he missed to claim in IT return?

Thanks in Advance