Note: This applies to DocuShare 4.x, 5.x, 6.x and 6.5.x
Issue:
Even when writer and/or manager permission is given to the Guest user and/or All Users and Guest group, the Guest (Anonymous) cannot add content in DocuShare (this includes calendar events).
Solution:
The Guest account is a special (built-in) read-only account by design.
To allow users to have the ability to add content in DocuShare they must be logged in with a valid user account and have the required permission to the container. (not browsing the site as Guest\Anonymous user)