A family of Microsoft products that enable users to capture, organize, and reuse notes electronically.
I had exactly the same problem. Although the error message said that I did not have permissions for this notebook, only one section in the notebook was affected, all the others were fine (all pages in the section had the problem). Logging into office.com allowed me to access the cloud version and make changes, including changes to the buggy section. The changes were sync'ed to the iPad in all sections except the buggy one.
I was able to solve the problem by uninstalling OneNote and reinstalling it.
P.S.: when I first logged into office.com, I couldn't access the OneNote backups, I got an error saying that the servers were down. When I tried later again it worked and I got the result described above. Maybe trying to change that notebook while the servers were down trigged the bug?