Haven't built Math::Pari for a while - last time I did build it I had good results following the instructions for the "manual procedure" that you'll find in the INSTALL file in the Math::Pari source tarball. (This way you don't have to actually build libpari.)
I didn't run './Configure' as mentioned in step b), and I didn't bother with 'make test' as mentioned in step c).
Have you tried that approach ? If so, at which step did you strike trouble ?