Sandia has migrated the Xyce web site to a different content management platform than the one we've been using for years, and the migration has not gone smoothly. We were only just made aware that the migrated site had gone live this week, and only just discovered today how broken it is. We are working on getting it back to normal now.
In the meantime, none of the download links for source code are working, and some of the download links for binaries are broken or point to the wrong version.
We apologize for the inconvenience, and will work to get it back on line as soon as possible.