Try to download all the packages and install them with the command line:
dpkg -i "xxx.deb" (be sure to be root with "sudo gainroot" before)
in this order : tcl, tk, tcltls, libsnack2, amsn
I got this problem and mention it to the developer on the amsn forum.
I think you do better to post directly on the amsn forum, the developer needs some feedbacks and for the moment I have not seen anybody else than me to posts comments.