diff --git a/scripts/ems/experiment.perl b/scripts/ems/experiment.perl
index c5bddc65a5..cb35cfb386 100755
--- a/scripts/ems/experiment.perl
+++ b/scripts/ems/experiment.perl
@@ -835,9 +835,9 @@ sub draw_agenda_graph {
 		$step .= " (".$RE_USE[$i].")" if $RE_USE[$i];
 
 		my $color = "green";
-		$color = "lightblue" if $RE_USE[$i];
 		$color = "#0000ff" if defined($DO{$i}) && $DO{$i} >= 1;
 		$color = "#8080ff" if defined($DONE{$i}) || ($RE_USE[$i] && $RE_USE[$i] == $VERSION);
+		$color = "lightblue" if $RE_USE[$i] && $RE_USE[$i] != $VERSION;
 		$color = "red" if defined($CRASHED{$i});
 		$color = "lightyellow" if defined($PASS{$i});
 		
diff --git a/scripts/ems/support/report-experiment-scores.perl b/scripts/ems/support/report-experiment-scores.perl
index 29cbdea595..fddd02fb39 100755
--- a/scripts/ems/support/report-experiment-scores.perl
+++ b/scripts/ems/support/report-experiment-scores.perl
@@ -64,7 +64,7 @@ sub extract_nist_bleu {
 	$bleu = $1*100 if /BLEU score = (\S+)/;
 	$ratio = int(1000*$1)/1000 if /length ratio: (\S+)/;
     }
-    if (!$bleu) {
+    if (!defined($bleu)) {
 	print STDERR "ERROR (extract_nist_bleu): could not find BLEU score in file '$file'\n";
 	return "";
     }
diff --git a/scripts/ems/support/run-command-on-multiple-refsets.perl b/scripts/ems/support/run-command-on-multiple-refsets.perl
index 1a7ef9e8e7..7590e72a1a 100755
--- a/scripts/ems/support/run-command-on-multiple-refsets.perl
+++ b/scripts/ems/support/run-command-on-multiple-refsets.perl
@@ -6,6 +6,11 @@
     unless scalar @ARGV == 3;
 my ($cmd,$in,$out) = @ARGV;
 
+die("ERROR: attempt to run on multiple references, but there is only one")
+    if -e $in && ! -e "$in.ref0";
+die("ERROR: did not find reference '$in.ref0'")
+    unless -e "$in.ref0";
+
 for(my $i=0;-e "$in.ref$i";$i++) {
     my $single_cmd = $cmd;
     $single_cmd =~ s/mref-input-file/$in.ref$i/g;