Mac Folders Getting Strange Names on Windows

Sometimes when I download something using a Mac program to my Drobo FS over AFP, if I look at the share from a Boxee Box or from a Windows machine (both over SMB), some of the folders (but not all of them, despite all be created in the same way) have strange short names when viewed on Windows, instead of their real file names. For instance, a folder for the movie 12 Angry Men (which I ripped from my DVD collection use RipIt) is “12 Angry Men (1997).dvdmedia” on the Mac becomes something like AQ2F29~P on the SMB share. Any idea why this is?