Troubleshooting another issue related to TinyMCE on my WP 3.5 install, went back to an old version (I believe it was 1.2). When I went to do the upgrade, the following showed up in my error log:
PHP Fatal error: Call to undefined function sp_tinymce_do_upgrade() in /wp-content/sp-resources/forum-plugins/tinymce-richtext/sp-tinymce-plugin.php on line 88
Any idea what that might be about?