diff -Nru gtk-sharp-2.12.8.orig/glib/Marshaller.cs gtk-sharp-2.12.8/glib/Marshaller.cs
--- gtk-sharp-2.12.8.orig/glib/Marshaller.cs	2009-01-30 20:51:10.000000000 +0100
+++ gtk-sharp-2.12.8/glib/Marshaller.cs	2009-03-25 17:01:55.000000000 +0100
@@ -312,7 +312,7 @@
 
 		public static IntPtr DateTimeTotime_t (DateTime time)
 		{
-			return new IntPtr (((long)time.Subtract (local_epoch).TotalSeconds) - utc_offset);
+			return new IntPtr (((int)time.Subtract (local_epoch).TotalSeconds) - utc_offset);
 		}
 
 		public static DateTime time_tToDateTime (IntPtr time_t)