Practical Problem on I TAX

Hi everyone I am waiting PE II result having basic knowledge of Income Tax(theoritical) but now i facing practical problem which are bellow..
    Mr x (a small business man) was file ROI for P/Y 2004-05,being encashment of TDS ( his gross total income is less than Max. amount not chargable to tax). Now Q arise, is it mendotery for Mr. X to file ROI for P/Y 2005-06, although his gross total income for the A/Y 2006-07 is less than Max. amount not chargable to tax.
          Dear friends please replay me as soon as..... 8)