http://www.google.com/search?hl=en&q=Vista+WLInstaller finds there are issues with this and Vista 64 bit. Then I go back to your post to check what version of Vista you have. No mention of it.

I also see there are issues like this on many homebrew machines. Your post doesn't tell a word about the machine.

Here's the forum note about what you need in your posts -> Note: If you're asking for technical help, please be sure to include all your system info, including operating system, model number, and any other specifics related to the problem.

Bob