Advanced Guestbook hack?

I have a problem with my Advanced Guestbook 2.3.1.
The thing is some days ago someone updated the
page 5000 times with POST requests.

I thought this was just a bug from someones webbrowser
(or something like that). I didn't care..

But now when I looked again I saw 2 more guys trying
the same thing? I have like 20000 POST request on my
guestbook... (they dont "post" anything btw just POST
requests.)

What are they looking for? Have Advanced Guestbook
password problems or something??

Should I be afraid?

/David

oh shit

maybe you should activate your floodcheck ..... and make use of your min message length option ..... you could also ban those ip's