I downloaded the Dr. Horrible soundtrack on Amazon. I had to use the Amazon MP3 downloader to buy an album as a single unit, and the Ubuntu version was for 7.10. (Old!) They had one for Debian Etch, so, being stubborn and not using XP, I brought up a VirtualBox Etch instance and downloaded the album from there. To get the shared folders to work I had to do the Install Additions thing. The install additions button mounts a disk image of the installers. The Linux version was a bash script and required the GNU compiler(s? I just installed both and it was fine) and kernel headers. It installed a kernel module, necessitating a reboot, and then I could successfully mount my shared folder as described in the manual. (Link is pdf.) Hooray stubbornness!