You can't apply a version 3 backup onto a version 4 system...bad things will happen.
the procedure should be to apply the version 4 upgrade to you existing version 3 unit, and the configuration will be migrated to version 4. Then take another backup.
Tried booth ways, upgrading a current install as well, same result.
You will have to do it manually.
I know this is a pain, but the advantage is that it will be set up from a clean install rather than a migration, which introduces extra layers of complexity that may potentially cause issues as well.