It seems like you'd need to do 'Administer CiviCampaign' to get it going. What I did was enable that for the user group and then hid the admin stuff from the contributor role for editing the navigational menu
As Demerit mentioned, you have the same issues I reported. I don't think it's about the number of fields that's the issue, but the combination of data types. If you are receiving that error, be careful if your site is live because some of your cases will hit an error and you won't be able to view the case page.
Here's what I did:
If possible, you will want ...