The latest WordPress 3.9 alpha greatly influences the activation of XenWord. The code was modified slightly so that the activation error no longer happens. This latest version is available to all purchasers and works fine on non-multisite installations.
This version is for testing WordPress 3.9. Please let me know if you find any bugs.
Important: The gravatar bug for WordPress members continues to be an issue in 1.0.1. If your WordPress database is blank and only the XenForo members log into the site then there is no issue.