If the waypoints transfer normally, the process is not visible in easygps, so there's no difference when it doesn't work. Using GSAK (which I only downloaded after this problem arose) there is no error message either, and the graphics look convincing when I press "send".
I do have the trips and waypoints disk, but my pc won't read it for some reason. Its absence has never been a problem before, but if there is a way of downloading its contents from Garmin I would like to know about it just in case...