I have just added a Win 2003 R2 server as a second DC in a domain which previously had just a single DC running Win 2003 (not R2).
When I attempt to edit a remote file with a script extension (e.g. .cmd) I get an error box saying "Windows cannot access the specified device, path or file. You may not have the appropriate permissions to access the item." I first noticed this when attempting to edit a logon script within the Group Policy Editor, but it happens with any remote file, whether I use a UNC path or a mapped drive to access it. I can create, delete and rename script files, and when I change the extension to .txt I can edit them and then rename them back to their previous extension.
I am doing all the above with the domain administrator account on the server running R2. If I log in to the non-R2 server with the same account I can edit script files (both local and remote, including ones physically held on the R2 server). I can also edit the same files remotely when logged in (with the same account) to a Windows XP client.
I will try to check here for answers as often as possible, but please be patient if I don't get straight back to you since I only work part-time on this network.