Substance is an external tool for making textures/materials.
I see some Paragon assets listed in your log, so my theory is that the substance plugin was used to create some of those, and there is something in those materials that references/relies on the substance plugin.
What I’d try is to package a new/blank project just to check if packaging is working.
Then I’d add the paragon character to the new project and see if those errors pop up.
If they do I’d crack open the materials that came with the paragon character, see if they compile successfully, and look for any broken/missing nodes.