Import Tool Upload Error (WordPress XML)

Hi all, when I try to import some pages and posts with the Import tool (Tools > Import > WordPress). I should add this is on a self-hosted installation and I’m trying to import sample files for the Radiant 2.0 theme.

At first it was saying it couldn’t find (or create, I forget) /uploads/2012/08 so I made that via ftp. Now I get this error:

Sorry, there has been an error.
The uploaded file could not be moved to /home/virtual/site673/fst/var/www/html/wp-content/uploads/2012/08.

If I upload the .xml file manually how do I get WordPress to actually import the pages, posts, etc.? If I can’t do that, does anyone know what I can do to get the Import tool to work?