Hi Aron,
That link is for a **very** old version of STRUCTURE.
I'd recommend compiling the latest from source.
You can get the source code from
this link, which can be accessed from
this page. You should just need "GNU Make" and a C compiler like GCC. Provided you are on a 64bit system, the resulting binary will also be 64bit.
You can find instructions on
this helper script from
Structure_threader (or you can simply run that script and it will take care of downloading and compiling STRUCTURE for you).
Best,
Francisco
PS - Alternatively, if you install Structure_threader via pip (pip3 install structure_threader --user), it will also install a 64bit copy of STRUCTURE on your system under ~/.local/bin.