You're not loading the new file into cID3.
Code:
Private Sub LblSave_Click()
 Dim lis As Long
 If (cID3 Is Nothing) = False Then Set cID3 = Nothing 'close any open file
 For lis = 0 To FileMP3.ListCount - 1
  sFileMP3 = FileMP3.Path & "\" & FileMP3.List(lis)
  Set cID3 = New clsID3
  With cID3
      If .LoadFile(sFileMP3) Then
      '.Title = TxtTitle.Text
      .Artist = Split(LblInfo(0).Caption, "//")
      .AlbumTitle = LblInfo(1).Caption
      .Year = IIf(Val(LblInfo(2).Caption) > 0, Val(LblInfo(2).Caption), Empty)
   If .WriteFile Then
       Beep
   Else
       MsgBox "Error"
   End If
   End If
  End With
  Set cID3 = Nothing
  TxtInfo.Visible = False: TxtInfo.Text = "": LblSave.Visible = False
 Next
End Sub