The hardest part of using the guestbook in a different movie clip will be to get all of the path names correct. You should make sure that you've got it working in it's basic form - then experiment with using it in different locations. It will be possible to use the guestbook even if you load the GuestBook dynamically with LoadMovie. But the Paths do get tricky.
It's important to give every Movie clip your using an Instance Name - then reference that Instance name in the paths that you are using.
Their are a couple of similiar threads on this, here's one:
http://www.flash-db.com/Board/index.php?board=2&action=display&threadid=34&start=0One of the easiest ways to use is using the 'This' path. So if your loading the Guestbook into a movie clip. You can place something like this on the first frame:
NumLow = 0;
NumHigh = 10;
loadVariablesNum ("GuestBook.php?NumLow="+NumLow+"&NumHigh="+NumHigh+"&R="+random(999), this);
stop();
Notice how "This" replace's the "0" - that was their before.