I think if I remember correctly you have to take ownership of the files on the Vista machine. Navigate to the Folder or Files you want to edit right click and select Properties. In the properties window, select Security Tab, Click the Advanced button in the Security tab. In the Advanced Security Settings, select Owner tab. Here you can view the current owner of the file and also the option to change owner. Click the Edit button at the bottom. Then you can select the new owner of the file which would be your Vista login and apply the settings. You get a security warning that you need to close the file and open it again for settings to take place. Now the ownership of file is changed to your vista user and you can edit them freely. Please note only users belonging the administrator group can take ownership on any windows file according to the default group policy on windows vista. So you need to be an administrator to take ownership.