We recently released SocialEngine 4 Beta 2, available for download from your client area. If you had any issues with the initial release, we recommend a clean reinstall. If you do install the new beta in the same directory as the old one, make sure to remove the /application/settings/database.php file.
Please send us bug reports (and some virtual love if you’d like) through the email provided in the client area so we can continue improving SocialEngine. Thanks for the great feedback so far!
UPDATE: We recommend waiting for the final release of SocialEngine for use on any production websites. There will be an upgrade path from the beta to the final.