- You also have to get the MIME-Base64 package
  (http://www.perl.com/CPAN/modules/by-module/MIME/)

- Unpack it:

    gzip -dc MIME-Base64-*.tar.gz | tar xvBf -

- Install it:

    cd MIME-Base64-*

  Then, as above, either

    perl Makefile.PL

  or

    perl Makefile.PL PREFIX=/some/dir

  Continue:

    make
    make test      (it should print 'All tests successful.')
    make install

  Now MIME-Base64 should be installed and working.