Well, nothing obvious jumps out at me. And the jar contains .so files that should work on both 32 and 64-bit flavors of Linux.
Are you able to test the .so files on your computer and see if there's an architecture incompatibility?
I've pulled the relevant .so files out of the jar.
ldd outputs the following for each of them:
linux-gate.so.1 => (0xb7782000)
libstdc++.so.6 => /usr/lib/i386-linux-gnu/libstdc++.so.6 (0xb74a4000)
libc.so.6 => /lib/i386-linux-gnu/libc.so.6 (0xb72fb000)
libm.so.6 => /lib/i386-linux-gnu/libm.so.6 (0xb72ce000)
libgcc_s.so.1 => /lib/i386-linux-gnu/libgcc_s.so.1 (0xb72b0000)
not a dynamic executable
Examining the .so file that is placed in my /tmp directory by the installer during runtime yields the latter output, indicating that it is the 64-bit library.
Why would the installer be mistaking my system for an 64-bit arch? Is there a way to force it to use the 32-bit .so?
Got it working via installing through one of my other boxes (which happens to be 64-bit). Multiplayer missions still failed to download but that's not a huge deal right now.
Had to install the 32-bit packages for Jansson and Lua manually, the program wouldn't start without them.
Off to bed now, I'll report back further at a later time.