Hard to say. There are probably some invalid entries in one of the lists.
Email me your orginal .backup file and I can look at what is wrong in it.
I know that I'm late for help you but I hope it will help somebody else.
I had the same error. The problem was the ExtendedList. You should try this:
1) Try to import the configuration without the ExtendedList. Then save the configuration.
2) If it's work (no errors) try this:
- Check your old ExtendedList file for a mistake (p.ex: two * characters in the end of your line or two space)
You can also check directly on your V7 version when the error occur in: Policy/Lists/Customs Lists/Extended List Elements/Imported.ExtendedList. Then you have so found an incomplete line (without Protocol, URL or Categorie). Then you have to correct these line in you old ExendedList and import it again.