Try to do with emmc same thing as with rootfs image -> turn off phone -> start flasher with emmc and start phone with u-key+connecting usb.

Check usb port you are using (recommended is that you use the main usb ports, normally in back of desktop pc)

If still fails then try live linux cd and flashing from there.

.edit
Oh dear god. Did you read wiki?
http://wiki.maemo.org/Updating_the_t...mware#Option_3
"...but the eMMC image stays at "no suitable device found. Waiting"....move onto option 4. "
Try first stuff from there as I said and then come here to ask more questions.