Hi
this is your code (you've attached):
form net_due_date tables in_tab structure itcsy
out_tab structure itcsy.
data: lv_basedate like sy-datum,
lv_payterms type i,
lv_duedate like sy-datum.
read table in_tab with key name = 'BASEDATE'.
move in_tab-value to lv_basedate.
read table in_tab with key name = 'PAYTERMS'.
move in_tab-value to lv_payterms.
lv_duedate = lv_basedate + lv_payterms.
read table out_tab with key name = 'DUEDATE'.
out_tab-value = lv_duedate.
modify out_tab index sy-tabix.
endform.
Now you should consider the routine get a value in output format, so probably these lines
read table in_tab with key name = 'BASEDATE'.
move in_tab-value to lv_basedate.
doesn't work well as in IN_TAB-VALUE there's a data in format DD.MM.YYYY and not YYYYMMDD
so I believe you need to transform all values from sapscript in the internal format
Max