I deleted my original sys-net and sys-fw and I received similar errors. What I did to fix it was
dom0$ sudo nano /etc/qubes-rpc/policy/qubes-update-policy and fixed the command which was pointing to the wrong sys-net. -- You received this message because you are subscribed to the Google Groups "qubes-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to qubes-users+unsubscr...@googlegroups.com. To post to this group, send email to qubes-users@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/qubes-users/24b75246-139a-43ee-a740-b99f7d740e92%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.