When a bookmark with an incorrect URL is used, Mozilla responds with a dialog box that says "<resource> was not found, please check the URL and try again." In this case, after clicking ok, the user should be presented with an opportunity to correct the URL. Two ways that this can be done: 1. URL be displayed in the URL Bar, or, 2. The bookmark manager, and properties dialog for the bookmark be opened
*** This bug has been marked as a duplicate of 28586 ***
28586 is very much related to this bug, but on a much broader level. It doesn't say much about incorrect bookmarks in particular ... could this be more useful as a dependency under it?