@MayorMcCheezewiz
The KoboRoot.tgz file copy in your .kobo folder should auto-reboot your reader when you unplug it from the computer.
During this reboot, your Aura HD installs what's insinde the .tgz file and the delete it. That's normal, as the reader is configured to auto-reboot when a .tgz file is found. If the .tgz file would remain here...you would have an endless bootloop