I recently upgraded to Omeka 1.2.1, which went fine and after the upgrade, everything was working okay. However, after I attempted to install a plugin (I believe it was the Docs Viewer, but it may have been Dublin Core Extended) I now get this error message:
Fatal error: Call to undefined function spl_object_hash() in /var/www/html/omeka/application/libraries/Omeka/Plugin/Loader.php on line 123
Any ideas on how to move past this? Many thanks.