You need to use 9.5 tools, as found at the ME thread, not 10.0 or anything else. Enable that BIOS option and then use Flash Programming Tool with "fptw -d spi.bin" command. If that fails, try "fptw -me -d me.bin". Compress and attach the resulting file.

Are you using a modded BIOS or similar? I doubt that these options appear on stock Acer BIOS. Have you tried flashing the latest from Acer first? If no, I suggest you do that. If yes, try this:

1. Download the attachment and place the "efi" folder at the root of a USB drive
2. Boot from the USB drive while the system starts
3. Run "setup_var 0x1EE 0x01" and reboot manually
4. Run Flash Programming Tool with the command "fptw -me -d me.bin"
5. If it completes successfully, compress & attach/upload "me.bin" file

It seems that the BIOS does not actually enable ME Re-Flash, that option does nothing. The other solutions require physical access to the motherboard. I don't know if you're comfortable with such things.

Physical access means that you would need to open the laptop and mess with the motherboard. One requires shorting two pins at the motherboard audio chip while the system starts and the other completely desoldering the SPI chip to use a hardware programmer.