"You don't have a Perl Package Manager you can use to install Math::Pari? That's how I get my packages. It even notes any dependencies you need for packages you want to install and automatically installs those as well, preventing problems like this."

Both ActiveState and Strawberry Perl have shipped with PPM and cpan for several years now. ActiveState doesn't ship with a C compiler or build tools, though they can be installed via ppm MinGW though currently only for the 32bit platform (note OP is using a 64bit perl), if you want to work with ActiveState 64bit you have to install this yourself.

With a little effort installing modules and their dependencies via cpan is reasonably straightforward. IMHO any automated system for module installation is going to have it's short comings, and for cpan that (again, IMHO) is the level of verbose output you get on failure. It seems simply to confuse those who aren't used to software compilation. In other words those who are new, and this can be very discouraging. Perhaps we can work on that.

Some of the popular PPM repos have been reported to me as 'out of date' or 'behind the times' recently. Part of that is perhaps due to them being run by individuals. I'm currently drafting a module installation tutorial covering modern module installation methods, and a FAQ on the subject. This will be posted for critique in the usual place before it makes it to tutorials.