You don't say what year/model your computer is or what Windows version your trying to install or what your doing or how far you are in the install so all we can do is to suggest you either keep trying as it's around a 700MB file and Apples servers are extremely slow for some people or use the 3.0 files that are already on your 10.6 MacOS installer disk.
Just skip the download option and select "I already have the drivers.." and continue the install.
I'm having the same problem except that I can't find / don't have my OS X installation disk (it might be in storage several hours away - I just moved) but I NEED to get Windows on my mac ASAP for my job.
Any idea? Is there another place to download the windows support besides through the bootcamp assistant (since it keeps saying it's not available)?
I am on a Macbook (7.1?) using OS 10.6.8. Something that recently profiled my system said I had a Macbook 7.1 (not referring to the OS), perhaps this is the generation and will tell you specifically which one I have. I got it in Aug '10.
Go to the Apple icon menu (upper left corner) and select "About this Mac"/ then "More Info...." and that will tell you every thing you ever wanted to know about your Mac.
Just look at the Model Identifier and that's your "version" #.
Unless you know anyone with another copy of a retail or upgrade 10.6 installer disk then your out of luck as the 10.6 MacOS installer disk has the ONLY 3.0 copy of the file which is needed before you can update to the other versions. The updates (3.1, 3.2, etc) will not work without 3.0 already installed. You cannot get it through Apple via any download.
Other options are pay another $30 for another copy of 10.6 or Yahoo/Google it and put up with possible Trojans, etc, downloading it off the open net.
If your computer came with 10.6 installed from the factory you can contact Apple and they will sell you another copy of the original disk's that came with the computer, which won't help much if your in a hurry.
(By the way your original disks included your Hardware Test disk if you ever have an issue to check your computer for possible hardware errors so you want to always keep your original disk(s) with you just in case, not to mention if you wanted to re-install 10.6 again.)