Movable Type treats its user's content as sacred and as a result does not modify, add or delete templates automatically under any condition, including upgrade. Therefore users upgrading from a previous version of Movable Type will not have the required Page Archive Template installed, and therefore will be unable to publish pages. You can create and save them, but not publish them.
To fix this issue, please install the Page Archive Template manually.
Submit a User Contributed Note
User contributed notes are a great way to share the knowledge you have gained in using Movable Type.
If you have a technical question or problem, please visit Movable Type Support.