PHP error log shows this:
[Thu Jan 15 14:03:35 2015] [error] [client x.x.x.x] Default exception handler: Acci\xc3\xb3n desconocida Debug: \nError code: unknowaction\n* line 463 of /lib/setuplib.php: moodle_exception thrown\n* line 545 of /mod/forum/post.php: call to print_error()\n, referer: http://campus.xxxxxx.com/login/index.php
[Thu Jan 15 14:04:02 2015] [error] [client 177.249.4.119] Default exception handler: No se puede encontrar registro de datos en la tabla course_modules de la base de datos. Debug: SELECT * FROM

WHERE id = ?\n[array (\n 0 => false,\n)]\nError code: invalidrecord\n* line 1451 of /lib/dml/moodle_database.php: dml_missing_record_exception thrown\n* line 1427 of /lib/dml/moodle_database.php: call to moodle_database->get_record_select()\n* line 183 of /availability/classes/info_module.php: call to moodle_database->get_record()\n* line 268 of /calendar/lib.php: call to core_availability\\info_module::is_user_visible()\n* line 91 of /blocks/calendar_month/block_calendar_month.php: call to calendar_get_mini()\n* line 288 of /blocks/moodleblock.class.php: call to block_calendar_month->get_content()\n* line 230 of /blocks/moodleblock.class.php: call to block_base->formatted_contents()\n* line 962 of /lib/blocklib.php: call to block_base->get_content_for_output()\n* line 1014 of /lib/blocklib.php: call to block_manager->create_block_contents()\n* line 392 of /lib/outputrenderers.php: call to block_manager->ensure_content_created()\n* line 36 of /theme/essential/layout/includes/header.php: call to core_renderer->standard_head_html()\n* line 27 of /theme/essential/layout/frontpage.php: call to require_once()\n* line 915 of /lib/outputrenderers.php: call to include()\n* line 845 of /lib/outputrenderers.php: call to core_renderer->render_page_layout()\n* line 101 of /index.php: call to core_renderer->header()\n, referer: http://campus.xxxxx.com/login/index.php