Thanks for the video, this is a great help.
It looks like you have no comment list at all on your guestbook page.
There are 2 more things to check:
1. Please have a look if the comments are enabled on the guestbook page.
To enable it edit the guestbook page. There you can find a box called “Discussion”, if you cannot see it you probably have to enable it in the screen options in the top right corner. In the discussion box please have a look if “Allow comments” is enabled.
This option should be overwritten by the guestbook option “Allow comments on the guestbook page” but perhaps something isn’t working correct.
2. What theme are you using?
Does your theme have a special options page where you can change the discussion settings? If this is the case the theme option overwrites the discussion option of the page.
I think the theme is the problem, you can also read this in all the other posts in this thread.