diff --git a/src/lib/Hydra/Helper/Nix.pm b/src/lib/Hydra/Helper/Nix.pm
index a27f9711..321e874a 100644
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -50,7 +50,7 @@ sub queryPathInfo {
 
     close FH;
 
-    die unless defined $hash;
+    die "path $path does not have a hash" unless defined $hash;
 
     return ($hash, $deriver, \@refs);
 }
diff --git a/src/script/hydra_scheduler.pl b/src/script/hydra_scheduler.pl
index a54afa70..5b798c73 100755
--- a/src/script/hydra_scheduler.pl
+++ b/src/script/hydra_scheduler.pl
@@ -366,7 +366,6 @@ sub inputsToArgs {
 
 sub permute {
     my @list = @_;
-    print scalar @list, "\n";
     for (my $n = scalar @list - 1; $n > 0; $n--) {
         my $k = int(rand($n + 1)); # 0 <= $k <= $n 
         @list[$n, $k] = @list[$k, $n];