Thanks for your earlier reply. I think I've diagnosed the trouble. I am working from a workstation on my (self installed) home network whilst the tracks I'm trying to alter are on the main server. I have previously had problems where my (obviously wrongly configured) network won't allow me to execute certain functions accross the network. I think this is one of them (I can alter them on the server, no prob). So bloody simple, I should have checked it earlier. I'm so sorry to have wasted your time. I guess even running through the problem with someone else helped me to solve it though, so thanks again. Cheers mate!