I just logged onto the first X64 based machine with libvirt (0.3.3-18.5) installed on it and I am only seeing the X64 based version of the shared library. Here is what I am seeing:
$ rpm -qal libvirt | grep libvirt.so
Is there any reason why the 32-bit version is not also installed?? My application is 32-bit based, so it will not work on this hardware because of this.