Oh! A Bravenet Guestbook? I never guessed. Thought you were using some kind of office live thing. When I know, I can find it, but it is badly mangled. This is probably something your editor does.
I found it searching for "x5cx2f", which is what OfficeLive apparently uses instead of "/". There seem to be numerous complaints about this, all (those I looked at) from Office Live users. Probably there is a setting you are missing. Say, you are using a "enter text" function instead of a "enter HTML code" function. Or something - I've never tried Office Live. Or perhaps you accidentally entered your code into a mess of other code. But yours was badly mangled.
If you look at the source code of your page, search for Bravenet Embedded Service Code, and compare the surrounding code with the original code you copied.
