Error starting airfoilspeaker on slackware

Hi when i try to start airfoilspeaker on linux slackware 12 i have this error:

./run_airfoilspeaker
Unhandled Exception: System.NotSupportedException: http://www.rogueamoeba.net/ping/versi...
at System.Net.WebRequest.GetCreator (System.String prefix) [0x00000]
at System.Net.WebRequest.Create (System.Uri requestUri) [0x00000]
at AirfoilServer.ApplicationSupport.UpdateChecker.CheckForLatest () [0x00000]
at AirfoilServer.ApplicationSupport.UpdateChecker.AutoCheckForLatest () [0x00000]
at AirfoilServer.GUI.AFSServerWindow.OnLoad (System.EventArgs e) [0x00000]
at System.Windows.Forms.Form.OnLoadInternal (System.EventArgs e) [0x00000]
at System.Windows.Forms.Form.OnCreateControl () [0x00000]
at System.Windows.Forms.Control.CreateControl () [0x00000]
at System.Windows.Forms.Control.WmShowWindow (System.Windows.Forms.Message& m) [0x00000]
at System.Windows.Forms.Control.WndProc (System.Windows.Forms.Message& m) [0x00000]
at System.Windows.Forms.ScrollableControl.WndProc (System.Windows.Forms.Message& m) [0x00000]
at System.Windows.Forms.ContainerControl.WndProc (System.Windows.Forms.Message& m) [0x00000]
at System.Windows.Forms.Form.WndProc (System.Windows.Forms.Message& m) [0x00000]
at System.Windows.Forms.Control+ControlWindowTarget.OnMessage (System.Windows.Forms.Message& m) [0x00000]
at System.Windows.Forms.Control+ControlNativeWindow.WndProc (System.Windows.Forms.Message& m) [0x00000]
at System.Windows.Forms.NativeWindow.WndProc (IntPtr hWnd, Msg msg, IntPtr wParam, IntPtr lParam) [0x00000]
at System.Windows.Forms.XplatUIX11.SendMessage (IntPtr hwnd, Msg message, IntPtr wParam, IntPtr lParam) [0x00000]
at System.Windows.Forms.XplatUIX11.MapWindow (System.Windows.Forms.Hwnd hwnd, WindowType windows) [0x00000]
at System.Windows.Forms.XplatUIX11.CreateWindow (System.Windows.Forms.CreateParams cp) [0x00000]
at System.Windows.Forms.XplatUI.CreateWindow (System.Windows.Forms.CreateParams cp) [0x00000]
at System.Windows.Forms.NativeWindow.CreateHandle (System.Windows.Forms.CreateParams create_params) [0x00000]
at System.Windows.Forms.Control.CreateHandle () [0x00000]
at System.Windows.Forms.Form.CreateHandle () [0x00000]
at System.Windows.Forms.Control.CreateControl () [0x00000]
at System.Windows.Forms.Control.SetVisibleCore (Boolean value) [0x00000]
at System.Windows.Forms.Form.SetVisibleCore (Boolean value) [0x00000]
at System.Windows.Forms.Control.set_Visible (Boolean value) [0x00000]
at System.Windows.Forms.Control.Show () [0x00000]
at (wrapper remoting-invoke-with-check) System.Windows.Forms.Control:Show ()
at AirfoilServer.Glue.AFSApplicationContext_GUI.Run () [0x00000]
at AirfoilServer.Program.Main () [0x00000]

I installed mono-1,2,6,6-installer from mono home page