No emulator programs working on Mac

Hi,

I can't seem to get any emulator programs to even extract. I get an error message that reads "Could not extract the file "snes9x-1.53-macosx113.dmg" from the archive "snes9x-1.53-macosx113.dmg.gz": The archive file is incomplete". I'm using The Unarchiver, FYI.

I'm sorry if this has been touched on before, but I didn't see it going through the boards. Is there anything I can do here?

Thanks,
Justin