Yikes! I web on a non-.mac server again. This has been discussed on these forums at considerable length in the past, so you might find that searching the forums for "iweb" will give you additional help besides my reply
iWeb was designed to work on the .mac platform and getting your stuff in the "correct spot" on a non-.mac server can be tricky because of the way iWeb does things.
iWeb has a "quirky" way of structuring your "website", and it is really designed to work well with the whole ".mac" experience. I'm not an expert with it (don't use it) but I have seen many "guides" to using iweb on "non-.mac" hosts on the web (that link Googles you a list of some of them), and IIRC, there are some well-documented workarounds you should become familiar with.
As you browse some of those Google results, and the previous iweb related threads on these forums, you might end up agreeing with others that iWeb is probably not the best way to go if not hosting on .mac (as one says, "it isn't pretty").
I suggest you take a look at NVU or KompoZer for a "good" WYSIWYG html creation tool if you are comfortable with iWeb but want to host on a non .mac server.