diff --git a/ChangeLog b/ChangeLog
index 3c8737481..d513af38a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2009-05-12  Mike Kestner  <mkestner@novell.com>
+
+	* glib/Value.cs: explicit exception for unknown props.
+	[Fixes #502043] Patch by Sebastian Dröge.
+
 2009-05-12  Mike Kestner  <mkestner@novell.com>
 
 	* glib/ValueArray.cs: make ctor(IntPtr) public for binding usage. 
diff --git a/glib/Value.cs b/glib/Value.cs
index 6d143f036..297ebfa5c 100755
--- a/glib/Value.cs
+++ b/glib/Value.cs
@@ -525,8 +525,13 @@ namespace GLib {
 		void InitForProperty (GType gtype, string name)
 		{
 			IntPtr p_name = Marshaller.StringToPtrGStrdup (name);
-			ParamSpec spec = new ParamSpec (g_object_class_find_property (gtype.ClassPtr, p_name));
+			IntPtr spec_ptr = g_object_class_find_property (gtype.ClassPtr, p_name);
 			Marshaller.Free (p_name);
+
+			if (spec_ptr == IntPtr.Zero)
+				throw new Exception (String.Format ("No property with name '{0}' in type '{1}'", name, gtype.ToString()));
+			
+			ParamSpec spec = new ParamSpec (spec_ptr);
 			g_value_init (ref this, spec.ValueType.Val);
 		}