I'd suspect that the two machines do have different architectures, the one with the incorrect results being on 64 bits.

That won't help too much - but maybe you can try further steps then to track the problem down, maybe to an library that isn't the right one for the given architecture.

Update: Sorry, I haven't noticed the uname -a in your original post, showing that the two machines are both x86-64. Still, it has to be something about the 64 bits libraries that differ on one machine.