If you use LiveEdit, IE and Vista to modify a file as a normal user, rather than the file being opened by the MS Office application, a page is displayed in IE with the message "Internet Explorer cannot display the web page" and the url like:
If you run IE as administrator then LiveEdit works correctly.
When originally installing LiveEdit, Vista required it to be installed by an administrator user so it's likely that this problem is due to a normal user login permissions not being able to run the LiveEdit extension or not being handle to identify the protocol handler nxedit.