--- master/lib/Munin/Master/Utils.pm.orig	2012-07-30 09:25:33.000000000 -0500
+++ master/lib/Munin/Master/Utils.pm	2012-08-05 14:07:57.236121331 -0500
@@ -904,6 +904,9 @@
 
 	my $storable_filename_tmp = $storable_filename . ".tmp.$$";
 
+	use Carp qw(cluck);
+	cluck "data is null at " unless $data;
+
 	# Write datafile.storable, in network order to be architecture indep
         Storable::nstore($data, $storable_filename_tmp);