Need help creating reminders on iOS 5
On the iPad Reminders app, there is no + button when viewing Completed tasks.
What happens when you click on Data? Can you then add items?
Edit
It looks like others are having the same problem. Does this reply work for you:

here's the solution that seems to work... have tried it, reversed it, and retried and it worked twice.  Turn on reminders in icloud.  go to reminder app.... + should now be there.  i then turned off reminders becasue it seems to just drain the battery... but select option to keep remdiners on the iphone when it prompts you.