REG UNLOAD Access Denied in CMD

Greetings,

I'm trying to write a simple batch file to load a hive from another hard drive, create a key, create a subkey, and then unload the hive. It all works well until I try to unload the hive. It says access denied. Here is what I have

REG LOAD HKLM\MINWIN E:\Windows\System32\config\system
REG ADD HKLM\MINWIN\xxxxxxxx\xxxxxxx\xxxxxx /f
REG ADD HKLM\MINWIN\xxxxxxxx\xxxxxxx\xxxxxx /f /v xxxxxxxxxxxxxxxx /t REG_DWORD /d 0
REG UNLOAD HKLM\MINWIN

Also, I am running these commands in cmd (ran as administrator) using windows 7.