Hi Ram,
You wont get the values inside the events at first, at last etc. The work areas will be reset.
In order to avoid, you need to move the values to another work area. Then it would work fine.
Loop at itab into wa_itab.
wa_itab1 = wa_itbab.
at new bukrs.
write wa_itab1-bukrs, wa_itab1-belnr, wa_itab1-gjahr.
endat.
endloop.