Index: mha4mysql-manager-0.53/lib/MHA/ManagerConst.pm
===================================================================
--- mha4mysql-manager-0.53.orig/lib/MHA/ManagerConst.pm	2012-01-09 00:06:46.000000000 +0900
+++ mha4mysql-manager-0.53/lib/MHA/ManagerConst.pm	2013-01-18 12:51:36.000000000 +0900
@@ -87,6 +87,7 @@
 our $log_fmt = sub {
   my %args = @_;
   my $msg  = $args{message};
+  $msg = "" unless(defined($msg));
   chomp $msg;
   if ( $args{level} eq "error" ) {
     my ( $ln, $script ) = ( caller(4) )[ 2, 1 ];
