Doh! Can you pop by IRC? I'm not sure who updated the Linux build last.. perhaps WickedShell or maci will know. It's possible that WickedShell updated it with a 32 bit build by mistake.
So the Linux build has been updated (and verified by BartK) using a Debian 64 bit VM. All you need to have installed yourself is libSDL-image, libSDL-mixer, libjpeg, and libcurl.