I'm not sure what the problem is, but the CPAN testers have successfully installed ExifTool on Win32 systems. Do you have problems installing other Perl modules?

At any rate, you can use exiftool without installing: Just run exiftool directly after extracting the tarball.

The only thing that the installation buys you is that it generates the POD documenation and man pages, and installs the libraries in the standard Perl location so you can access them as standard Perl modules. But none of this is required just to run ExifTool, and the included html documentation contains all the information of the POD and man pages.