Using Survey version = 2014012101
When in Preview mode, getting these warnings:

Notice: Undefined variable: submission in moodle\mod\survey\classes\view_userform.class.php on line 1057
Notice: Trying to get property of non-object in moodle\mod\survey\classes\view_userform.class.php on line 1057

Edit.- More errors:
Notice: Trying to get property of non-object in M:\server\htdocs\moodle27\moodle\mod\survey\classes\view_userform.class.php on line 1057
This page did not call $PAGE->set_url(...). Using http://192.168.1.11/moodle27/moodle/mod/survey/view.php

line 558 of \lib\pagelib.php: call to debugging()
line 734 of \lib\pagelib.php: call to moodle_page->magic_get_url()
line 3630 of \lib\navigationlib.php: call to moodle_page->__get()
line 3352 of \lib\navigationlib.php: call to settings_navigation->load_course_settings()
line 717 of \lib\pagelib.php: call to settings_navigation->initialise()
line 734 of \lib\pagelib.php: call to moodle_page->magic_get_settingsnav()
line 136 of \blocks\settings\block_settings.php: call to moodle_page->__get()
line 296 of \blocks\moodleblock.class.php: call to block_settings->get_content()
line 238 of \blocks\moodleblock.class.php: call to block_base->formatted_contents()
line 956 of \lib\blocklib.php: call to block_base->get_content_for_output()
line 1008 of \lib\blocklib.php: call to block_manager->create_block_contents()
line 361 of \lib\outputrenderers.php: call to block_manager->ensure_content_created()
line 6 of \theme\base\layout\embedded.php: call to core_renderer->standard_head_html()
line 877 of \lib\outputrenderers.php: call to include()
line 807 of \lib\outputrenderers.php: call to core_renderer->render_page_layout()
line 750 of \lib\outputrenderers.php: call to core_renderer->header()
line 2591 of \lib\weblib.php: call to core_renderer->redirect_message()
line 145 of \mod\survey\view.php: call to redirect()