The stacktrace is:

(Nereid:21003): GLib-GObject-CRITICAL **: g_value_unset: assertion 'G_IS_VALUE (value)' failed

(Nereid:21003): GLib-GObject-WARNING **: /build/buildd/glib2.0-2.40.0/./gobject/gtype.c:4210: type id '0' is invalid

(Nereid:21003): GLib-GObject-WARNING **: can't peek value table for type '<invalid>' which is not currently referenced

(Nereid:21003): GLib-GObject-WARNING **: /build/buildd/glib2.0-2.40.0/./gobject/gvalue.c:188: cannot initialize GValue with type '(null)', this type has no GTypeValueTable implementation

(Nereid:21003): Gtk-WARNING **: /build/buildd/gtk+2.0-2.24.23/gtk/gtktreedatalist.c:180: Unsupported type ((null)) retrieved.

(Nereid:21003): GLib-GObject-CRITICAL **: g_boxed_type_register_static: assertion 'g_type_from_name (name) == 0' failed

(Nereid:21003): GLib-GObject-CRITICAL **: g_value_get_boxed: assertion 'G_VALUE_HOLDS_BOXED (value)' failed

(Nereid:21003): GLib-GObject-CRITICAL **: g_value_unset: assertion 'G_IS_VALUE (value)' failed
Exception in Gtk# callback delegate
  Note: Applications can use GLib.ExceptionManager.UnhandledException to handle the exception.
System.NullReferenceException: Object reference not set to an instance of an object
  at Banshee.Sources.Gui.SourceView.OnRowExpanded (TreeIter iter, Gtk.TreePath path) [0x00018] in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceView.cs:401 
  at Gtk.TreeView.rowexpanded_cb (IntPtr tree_view, IntPtr iter, IntPtr path) [0x00000] in <filename unknown>:0 
   at GLib.ExceptionManager.RaiseUnhandledException(System.Exception e, Boolean is_terminal)
   at Gtk.TreeView.rowexpanded_cb(IntPtr tree_view, IntPtr iter, IntPtr path)
   at Gtk.TreeView.gtk_tree_view_expand_row(IntPtr , IntPtr , Boolean )
   at Gtk.TreeView.ExpandRow(Gtk.TreePath path, Boolean open_all)
   at Banshee.Sources.Gui.SourceView.Expand(TreeIter iter) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceView.cs:line 488
   at Banshee.Sources.Gui.SourceView.OnSourceRowInserted(System.Object o, Banshee.Sources.Gui.SourceRowEventArgs args) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceView.cs:line 454
   at Banshee.Sources.Gui.SourceModel.OnSourceRowInserted(Banshee.Sources.Source source, TreeIter iter, TreeIter parentIter) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs:line 112
   at Banshee.Sources.Gui.SourceModel.AddSource(Banshee.Sources.Source source, TreeIter parent) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs:line 232
   at Banshee.Sources.Gui.SourceModel.AddSource(Banshee.Sources.Source source, TreeIter parent) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs:line 225
   at Banshee.Sources.Gui.SourceModel.AddSource(Banshee.Sources.Source source) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs:line 192
   at Banshee.Sources.Gui.SourceModel+<OnSourceAdded>c__AnonStorey1.<>m__0() in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs:line 97
   at Hyena.ThreadAssist.ProxyToMain(Hyena.InvokeHandler handler) in /home/knocte1404/banshee2/src/Hyena/Hyena/Hyena/ThreadAssist.cs:line 103
   at Banshee.Sources.Gui.SourceModel.OnSourceAdded(Banshee.Sources.SourceAddedArgs args) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Sources.Gui/SourceModel.cs:line 96
   at System.Reflection.MonoMethod.InternalInvoke(System.Reflection.MonoMethod , System.Object , System.Object[] , System.Exception ByRef )
   at System.Reflection.MonoMethod.Invoke(System.Object obj, BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture)
   at System.Reflection.MethodBase.Invoke(System.Object obj, System.Object[] parameters)
   at System.Delegate.DynamicInvokeImpl(System.Object[] args)
   at System.MulticastDelegate.DynamicInvokeImpl(System.Object[] args)
   at System.Delegate.DynamicInvoke(System.Object[] args)
   at Hyena.EventExtensions.SafeInvoke(Banshee.Sources.SourceAddedHandler event, System.Object[] args) in /home/knocte1404/banshee2/src/Hyena/Hyena/Hyena/EventArgs.cs:line 55
   at Banshee.Sources.SourceManager.AddSource(Banshee.Sources.Source source, Boolean isDefault) in /home/knocte1404/banshee2/src/Core/Banshee.Services/Banshee.Sources/SourceManager.cs:line 183
   at Banshee.ServiceStack.Application.Run() in /home/knocte1404/banshee2/src/Core/Banshee.Services/Banshee.ServiceStack/Application.cs:line 108
   at Banshee.Gui.GtkBaseClient.Initialize(Boolean registerCommonServices) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Gui/GtkBaseClient.cs:line 193
   at Banshee.Gui.GtkBaseClient..ctor(Boolean initializeDefault, System.String defaultIconName) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Gui/GtkBaseClient.cs:line 96
   at Banshee.Gui.GtkBaseClient..ctor() in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Gui/GtkBaseClient.cs:line 88
   at Nereid.Client..ctor()
   at System.Reflection.MonoCMethod.InternalInvoke(System.Reflection.MonoCMethod , System.Object , System.Object[] , System.Exception ByRef )
   at System.Reflection.MonoCMethod.InternalInvoke(System.Object obj, System.Object[] parameters)
   at System.Activator.CreateInstance(System.Type type, Boolean nonPublic)
   at System.Activator.CreateInstance(System.Type type)
   at Banshee.Gui.GtkBaseClient.Startup() in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Gui/GtkBaseClient.cs:line 83
   at Hyena.Gui.CleanRoomStartup.Startup(Hyena.Gui.StartupInvocationHandler startup) in /home/knocte1404/banshee2/src/Hyena/Hyena.Gui/Hyena.Gui/CleanRoomStartup.cs:line 54
   at Banshee.Gui.GtkBaseClient.Startup() in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Gui/GtkBaseClient.cs:line 78
   at Banshee.Gui.GtkBaseClient.Startup(System.String[] args) in /home/knocte1404/banshee2/src/Core/Banshee.ThickClient/Banshee.Gui/GtkBaseClient.cs:line 68
   at Nereid.Client.Main(System.String[] args) in /home/knocte1404/banshee2/src/Clients/Nereid/Nereid/Client.cs:line 54
make: *** [run] Error 1