If you create a site or page name in iWeb 1.0.1 with an apostrophe as part of the name, and subsequently update to iWeb 1.1, then the web addresses (URLs) to your site/page will no longer be valid. This will break any existing bookmarks to the page. This occurs because iWeb 1.1 handles apostrophes differently than iWeb 1.0.1.
People who bookmarked your iWeb 1.0.1 site need to bookmark your new site published with iWeb 1.1.