Hi,
Please use the function module -> LAST_DAY_IN_PERIOD_GET. use any random period to get the 0FISCYEAR to 0FISCPER. Pass this value along with the 0FISCVER to the function module to get the last date in that period (type YYYYMMDD). Get the first four characters of this date and assign to the 0CALYEAR.
I presume that you are not using K4 as Fiscal year variant (if yes then there is no difference between the Fiscal year and calender year).
Regards
Sourav