Yeah I got that too. I just downloaded the zip file of all the drivers, the wifi one is in there. By the way the one in the zip is the slightly older one (17.x as I recall), my guess is the latest one (18.? producing the 404) isn't available yet for newer boxes.
When maintenance is being performed, it is possible that you can browse for new drivers but not complete downloads. A different server is used for the actual download. All you need to do is wait a while and it will work again.
P.S. The 18.2 drivers are posted there now.
The page is now operational, here is the link for you to download the driver based on your operating system:
If you have any problems with it please let me know.