Problem created by mixing relative and absolute paths

DirectoryNotFoundException was unhandled
Could not find a part of the path 'D:\Works\Nando\C#\Apps\Media Player\1\PMedia Player\PMedia Player\bin\Release\Release\Video\1\002. Configuring the Layout of Visu.mp4'.
//which is the full path of the selected file in the treeview

private void ListDirectory()
        {
            list.Nodes.Clear();
            var rootDirectoryInfo = new DirectoryInfo(Directory.GetCurrentDirectory().ToString());
            list.Nodes.Add(CreateDirectoryNode(rootDirectoryInfo));
        }

        private static TreeNode CreateDirectoryNode(DirectoryInfo directoryInfo)
        {
            var directoryNode = new TreeNode(directoryInfo.Name);
            foreach (var directory in directoryInfo.GetDirectories())
                directoryNode.Nodes.Add(CreateDirectoryNode(directory));
            foreach (var file in directoryInfo.GetFiles())
                directoryNode.Nodes.Add(new TreeNode(file.Name));            
            return directoryNode;
        }
private void list_AfterSelect(object sender, TreeViewEventArgs e)
        {
            WMPLib.IWMPPlaylist playlist = player.playlistCollection.newPlaylist("media_playlist");
            WMPLib.IWMPMedia media;
            //player.close()
            DirectoryInfo dir = new DirectoryInfo(list.SelectedNode.FullPath.ToString());
            if (list.SelectedNode.FullPath.Length!=0)
            {
            foreach (var file in dir.GetFiles())
            {                
                media = player.newMedia(Path.GetFullPath(Path.GetFileName(file.ToString())));
                playlist.appendItem(media);                
                path.Text=Path.GetFullPath(Path.GetFileName(file.ToString()));               
            }
            list.Visible = false;
            player.currentPlaylist = playlist;
            player.Ctlcontrols.play();            
            }else{
            MessageBox.Show("Directory not found!");
            }
        }