Index: trunk/ippScripts/scripts/detrend_norm_calc.pl
===================================================================
--- trunk/ippScripts/scripts/detrend_norm_calc.pl	(revision 17105)
+++ trunk/ippScripts/scripts/detrend_norm_calc.pl	(revision 17117)
@@ -181,4 +181,9 @@
 	my $normalisation = $normItem->{value}; # Normalisation for component
 
+	if ($normalisation == 0.0 or lc($normalisation) eq 'nan') {
+	    warn("Class $className has bad normalisation: $normalisation");
+	    exit($PS_EXIT_SYS_ERROR);
+	}
+
 	my $command = $commandBase;
 	$command .= " -class_id $className";