You haven't shown us the output from when you compile and test Math::PARI.

The usual sequence of commands is

perl -w Makefile.PL
make
make test
make install
[download]

So far we've only seen the perl Makefile.PL part.

Update: Looking at your perl -V output, you have cc=cl, which means you're running on Win32 with MSVC as the compiler, so you'll have to change the above to:

perl -w Makefile.PL
nmake
nmake test
nmake install
[download]

See also syphilis' node below.