Error 6006 is almost always resolved by updating the engine manually and ensuring a clean, administrator-level execution environment. Avoid running Nemesis from within mod manager virtual folders (e.g., MO2’s mods\Nemesis directory) — run it directly from its real install location.
The error message "Missing latest engine files" implies that the Nemesis engine cannot find the necessary data to launch, or it is conflicting with older files from previous versions. Error 6006 is almost always resolved by updating