can't upload pictures in guestbook!!

Everytime my self or some one is signing my guestbook at www.latinevent.com and they want to upload a picture i does not load. why is this happening? did i forget something or did i do something wrong?? your help will be greatly appreciated, thanks

Well after looking at it, you don't even have a folder named "public", make sure that that folder exists and that it is writeable. If I type http://www.latinevent.com/guestbook/public I get a 404 error saying that it does not exist