When visiting /forum I get:
Fatal error: Unsupported operand types in /home/account/public_html/drupal/includes/theme.inc on line 1071
PathInfo: forum is served by advanced_forum_forum_page, implemented by advanced_forum in /home/account/public_html/drupal/sites/all/modules/advanced_forum/plugins/tasks/forum.inc at line 61
When I load the Modules page, I get this after visiting /forum and getting that error above (did not before visiting the forum page), maybe it will help in debugging:
Notice: Undefined offset: 1 in advanced_forum_preprocess_views_view__advanced_forum_topic_list() (line 366 of /home/account/public_html/drupal/sites/all/modules/advanced_forum/includes/theme.inc).
Notice: Trying to get property of non-object in advanced_forum_preprocess_views_view__advanced_forum_topic_list() (line 367 of /home/account/public_html/drupal/sites/all/modules/advanced_forum/includes/theme.inc).
Advanced Forum 7.x-2.0+29-dev