I don't quite understand what you mean by "I tried to move the folder to the desktop"?
Did you actually go through the steps that I told you to do?
iWeb will actually save and you can save your work manually, but this will be saved to your domain.sites file, which is your iWeb data file which is found under your User/Library/Application Support/iWeb/domain.sites. Note that it is your User Library Folder and NOT your System Library.
You need to open iWeb and not save or move any folder to your desktop, but your need to select File and then use the 'Publish to a local folder' option and this will then create and publish your html and css files to your desktop.
If Filezilla is not working for you, then try downloading Cyberduck and use this instead. Once you have your site published to your desktop, then there should be no problem at all uploading all your html and css files to your host/server using Cyberduck.
Follow those steps and you should not have a problem, unless of course, you are trying to upload the wrong files? Cyberduck is probably easier to use and might be a better choice than Filezilla.
Also, there is no problem with compatibility and iWeb 08 and Snow Leopard. This only occurs with Moutain Lion as Roddy has already pointed out, but if you are not using Mountain Lion, then it is not applicable, but it works fine with Snow Leopard.
You can upgrade to iWeb 09 - version 3 if you want to, but this means purchasing either the iLife 11 or iLife 09 boxed set from Amazon - both contain iWeb 09, the latest version.