Thank you for contacting us for support. We did end up removing the cpanel importer tool a while back. The format of the cpanel backup/package changed dramatically between versions, so only the oldest of the old of cpanel backups would work anymore, and fail nearly always every other attempt. It was difficult to reverse-engineer an importer for the very old versions, and to re-write for newer versions is a very time consuming project.
If you have to have cpanel cpanel, and are willing to buy the needed plan from cpanel, it can be setup on DreamCompute and then that used to import from cpanel to cpanel. We can't fully support it but can guide you a tad, also having some knowledge in system administration would also be good for backups, etc.
You can send in a ticket here https://panel.dreamhost.com/index.cgi?tree=support.msg& and our support team will get back to you as soon as possible,