Hi- One thought I'm having is that you may be blocking the UnP ports on your Kaspersky Firewall. Try disabling the Firewall first. If it works, then we can go deeper into configuring the specific ports needed.
Thanks for the answer, I have tried disabling the Kaspersky Firewall but this does not alter the problem of the files being in accessible. I think the issue is one of accessibility in Vista, as the folder is always inaccessible, and confusingly this is even the case if I explore the network from the actual machine and try to access it! Any other suggestions? So far as I am aware the uPnP ports are configured correctly for this. Incidentally I just changed the router for a replacement Type N one, still Netgear though.
You do have to make sure that the folders you want to share with Sonos are checked for File Sharing. You also need to make sure that Sonos has the correct userid/password XXXXX the owner of the folder being shared. If you have more than one system on your network, check the Networking Panel to see if the folders you want to share with Sonos are showing up.
Also, check the permissions of the shared folder to make sure that others have read permission rights. If you right-clock on the folder and select properties you will be able to check that.