hmm very strange.
try a other usb port
try to rename the file
download it another time
be sure its in the last folder in the flasher directory(where the flasher exe file is)
be sure ovi suite isn't running
try to flash the emmc first and right after the fiasco with the-R (reboot) command at the end.
if this all doesn't work try it on a different os like win xp service pack 3
don't forget that under win 7 there are many problems .