ia32-libs-gtk should fix the problem. The problem was pretty basic: running a 32-bit executable on a 64-bit system without the proper libraries doesn't work.
My initial post might have been too hasty, but since I had a minor amount of difficulty finding a solution, I might as well answer. I ran
strace ./unetbootin-linux-494, which tells me:
execve("./unetbootin-linux-494", ["./unetbootin-linux-494"], [/* 33 vars */]) = 0
[ Process PID=5369 runs in 32 bit mode. ]
old_mmap(0x1020000, 4096, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0x1020000) = 0x1020000
readlink("/proc/self/exe", "/home/jb/Downloads/unetbootin-linux-494", 4096) = 43
old_mmap(0x8048000, 10891295, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x8048000
mprotect(0x8048000, 10891292, PROT_READ|PROT_EXEC) = 0
old_mmap(0x8aac000, 124071, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0xa63000) = 0x8aac000
mprotect(0x8aac000, 124068, PROT_READ|PROT_WRITE) = 0
old_mmap(0x8acb000, 4436, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x8acb000
brk(0x8acd000) = 0x8bfc000
open("/lib/ld-linux.so.2", O_RDONLY) = -1 ENOENT (No such file or directory)
_exit(127) = ?
Clearly the problem is that the
ld-linux.so.2 object doesn't exist on my system. Since that object is part of
ia32-libs, I installed that package. However, that isn't enough, because I then received this error:
unetbootin-linux-494: error while loading shared libraries: libgthread-2.0.so.0: cannot open shared object file: No such
file or directory
According to this bug report, however, the problem is because the
ia32-libs-gtk package needs to be installed as well. Once I installed that, the executable ran normally.