The application segfaults immediately on startup - I don't even get a GUI.

$ ./eschalon_book_2
Segmentation fault
$

Looks like it's a 64 bit audio problem.
$ LD_DEBUG=libs ./eschalon_book_2
....lots of output then finally...
13592: find library=libportaudio.so.2 [0]; searching
13592: search cache=/etc/ld.so.cache
13592: search path=/lib32/i686/cmov:/lib32/i686:/lib32:/usr/lib32/sse2:/usr/lib32 (system search path)
13592: trying file=/lib32/i686/cmov/libportaudio.so.2
13592: trying file=/lib32/i686/libportaudio.so.2
13592: trying file=/lib32/libportaudio.so.2
13592: trying file=/usr/lib32/sse2/libportaudio.so.2
13592: trying file=/usr/lib32/libportaudio.so.2
13592:
Segmentation fault

I have the ia32-libs package installed. Any thoughts on how to fix this?

Solved...

Some combination of following the instructions here:
http://gwos.org/doku.php/guides:64bit:eschalon_book_i

and making sure that the 3D drivers for your video card are working correctly. In my case
$ fglrxinfo
<print stuff about OpenGL drivers>

$ glxgears
(show rotating gears)