I've got the IS department at work on this now (unofficially) and their current suggestion that it could be caused by another program such as a virus checker running in the background which is stopping the file being accessed. To check for this you need to eliminate all processes other than explorer and systray before running Mover. To do this press ctrl-alt-delete which will bring up the close program dialog box. Then click 'end task' for every program except explorer and systray. Then cancel the close program dialog, run Mover and keep your fingers crossed. If it works, you can do the process again but this time just stopping one application at a time (or do a binary chop if you want to save time) until you find the offending application. My only doubt about this is that I can't see why it would only cause problems with the frog and not other pcf files.