raster export with transparency

My script to set the background color and then export with the bg_transparent parameter is nt working, any suggestions apprecited.


GLOBAL_MAPPER_SCRIPT VERSION=1.00

IMPORT FILENAME="E:\Windows\Documents\Downloads\test.ecw"

SET_BG_COLOR COLOR=RGB(255,255,255)

EXPORT_RASTER FILENAME="E:\Windows\Documents\Downloads\test2.ecw" TYPE=ECW BG_TRANSPARENT=YES