You don't need to extract the acmeinstaller file, just place it in Program Files/Palm, Inc, open up a terminal window and enter in the command to run it.
Of course, you do this after you have set up your cminstall folder on the touchpad.
A word of advice - I find it useful to have 2 copies of the rom you want to flash - one in the cminstall folder, and one in the root folder of the touchpad. This is because sometimes the flashing process with acme can be a bit funny, and it automatically deletes the files in cminstall once its done. I've flashed a couple of touchpads with acme and Android hasn't installed properly, so having a backup somewhere else on the touchpad is useful.
Lumia 820 - stock
HP Touchpad 16/32GB - webOS/Android