Hello
Try to set file name to screen file io_file by 'io_file = lv_file' instead of 'SET PARAMETER ID 'FIL' FIELD lv_file'
Or you can use Function module DYNP_VALUES_UPDATE in order to set file name to sreen field io_file.
BTW, SET PARAMETER ID 'FIL' FIELD lv_file', it don't work in POV.
BR
Vinh VO