Question about Preview issues

Today I have enabled the Advanced Guestbook (2.2) through my control panel at my webhosting company. I did not install it -- it was already preinstalled by my host.

I have customized the guestbook via the administration panel. I can post to the guestbook, and the email and comments seem to be functioning fine.

However, I have noticed that when I post to the book and click on the preview button, it does bring up my preview of my comment. But then when I hit the submit button on the preview screen it posts the comment twice to my book instead of just once.

If on the other hand, I just hit "submit" from the regular comment entry screen and don't preview the comment, the comment is just posted once.

Thanks in advance for any help you may provide.

A newbie