TagLib.Tag always empty on Windows Form project

Question

Well, I'm making a simple winform to create a text file containing paths to various songs. It's just a simplistic playlist for a visualizer/audio player that I've been working on (using XNA, C#, and Bass.Net). I'd like to use TagLib access and display song titles, artists, and to sort playlists.

This is the code that I've been using:

    private void button1_Click(object sender, EventArgs e)
    {
        selectPlaylist.ShowDialog();
        string filePath = string.Empty;
        if (selectPlaylist.FileName.EndsWith(".txt"))
        {
            StreamReader fInput = new StreamReader(selectPlaylist.FileName);
            playlistName = fInput.ReadLine();
            playlistNameTextBox.Text = playlistName;
            while (!fInput.EndOfStream)
            {
                filePath = fInput.ReadLine();
                if (!filePath.Contains(":\\")) continue;                   
                songInfo.Add(TagLib.File.Create(filePath).Tag); //List<TagLib.Tag>
                songs.Add(filePath); //List<string>
            }
            songNamesComboBox.DataSource = songs;
            fInput.Close();
            fInput = null; //don't even know if I need this
        }
    }

Regardless of what files I use, all of the Tag properties/attributes are empty. I created a console application and did the same thing (creating a file and saving its Tag to a variable) and was able to correctly access tag information.

TagLib.Tag tag = TabLib.File.Create("D:\\Music\\Electronic Music\\" +
    "Instrumental Core\\The Angels Among Demons.mp3").Tag;
Console.WriteLine(tag.Title);

I'm a bit new to C#, but I cannot figure what I've done wrong. Why would the latter (console application) work, but not my winform?