you don't HAVE to disable UAC, you can put the config file on the desktop, change the settings, save it, then put it back in the folder.
If you are running anything other then Vista/7 64 bit, then use the other reg. to check click on the start orb, right click on my computer and select properties.
look under System, and look for System type. if it doesn't say 64 bit operating system, then just run the regular reg file