When we use NOTES URLS in documents on the WEB or elsewhere most of our users are able to use the URLS just fine. However there is a subset of users who cannot paste a NotesURL into a windows Start Run box and have it open the notes document on Windows XP machines. So the same URL will work for most users on XP but other XP users cannot use it.
I am sure that there must be some XP windows setting that controls this but I have no idea where it would be. A Notes URL looks like this
(The link above has been altered and will not work, it is an internal address anyway)