The article goes over installing the Net::Amazon::S3 Perl module via WHM (which is handy for the cPanel users). However, if you’re not a cPanel user, you can install it via CPAN:
# perl -MCPAN -e 'install Net::Amazon::S3'
If you’d rather install it through Webmin, go to the ‘Others’ section, and click ‘Perl Modules’.
Overall, it’s a great post, and I’m glad Tim told me about it!