Error do Editor

System.IO.FileNotFoundException: File not found.
at Microsoft.VisualBasic.Interaction.Shell(String PathName, AppWinStyle Style, Boolean Wait, Int32 Timeout)
at SLRReditor2.Form1.ListBox1_SelectedIndexChanged(Object sender, EventArgs e)
at System.Windows.Forms.ListBox.OnSelectedIndexChanged(EventArgs e)
at System.Windows.Forms.ListBox.set_SelectedIndex(Int32 value)
at SLRReditor2.Form1.Button2_Click(Object sender, EventArgs e)
at System.Windows.Forms.Control.OnClick(EventArgs e)
at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks)
at System.Windows.Forms.Control.WndProc(Message& m)
at System.Windows.Forms.ButtonBase.WndProc(Message& m)
at System.Windows.Forms.Button.WndProc(Message& m)
at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)