This seems to work:
DateTime ldt_date
Date ltd_sys_date
ldt_date = DateTime( Date("Dec-31-2099") , Now())
ltd_sys_date = Date("Dec-31-2099")
if year (date(ldt_date)) = year (date(ltd_sys_date)) then
UPDATE MAIN
SET YTD_NO = nvl( YTD_NO , 0 ) + 1,
YTD_AMT = nvl(...