If you installed the old driver (the one for XP), or if you plugged RLink before installing the Vista driver, or if your user account management is not as admin as you think (often happens in Vista), then you might be unable to install it. Here some things to try for making it work:
1. Make sure you are logged as Administrator AND run the "RLinkUSBInstall.exe" using the "run as administrator" option.
2. Here is the uninstallation procedure to follow in case you have some wrong driver loaded:
2.1. Plug the RLink, and if any driver is loaded for it, go to the device manager and ask Windows to uninstall it. I don't expect that to have much effect, but it's cleaner to try it. If you see a "Jungo" section in the device manager, please also try to uninstall it. Then, unplug the RLink.
2.2. Remove all the files, directories and reg keys (using regedit.exe started as admin) in the list below. In DriverStore, try to remove the directories. If you cannot, remove as many of the files in them as you can. Also remove the registry entries if you manage to do it. You'll need to change the ownership to yourself, recursively, then give "everyone" the complete access to the keys/directories/files, then you should be able to remove them. Being an administrator is not enough with Vista. You have to trick it all the time. ;( Here is the list of things to remove if they exist:
files and folders:
2.3. When you have removed everything you can, run RLinkUSBInstall again (in admin mode, not just while being logged as admin) leave it at least 2 minutes to complete and then plug the RLink. Check that you see the BUSY LED turning ON (means the RLink is started) and then OFF. (means the USB enumeration has been done, and therefore that the driver is correctly loaded)