My question is not strictly Perl related.

Why do you need to use this server as outdated as it is? If you have a choice, don't.

If the ISP is receptive, ask them to update the server or to move you to one of their updated servers. Many ISPs who will refuse to update a server will be more than willing to move your stuff to a server with a more modern toolset. The reason for this is that they don't want to expose existing customers on existing servers to update issues like language compatibility changes and such. This is a particular issue for PHP, and somewhat for MySQL. It's usually not an issue for Perl but it can be if someone's uploaded binary modules of their own. These ISPs tend to keep the old servers around and do only OS-level security updates on them. When they outgrow capacity, the new servers are built to a newer spec. So when you update a site, asking to be moved to a different server sometimes works when asking for an update to the server you're on will not.

If someone insists that you use that specific server, perhaps you could explain the situation. If those things fail, I guess building your own perl and uploading it is an option. Some ISPs don't allow compiled programs to be uploaded. Some that do allow it don't allow new versions of tools already offered. You should make sure this is acceptable practice on the server if you can get an answer. If the ISP doesn't allow it and you're still under the gun to do the site, you might need to backport to the earlier perl.