=== modified file 'dhis-2/dhis-web/dhis-web-apps/src/main/webapp/dhis-web-visualizer/scripts/core.js'
--- dhis-2/dhis-web/dhis-web-apps/src/main/webapp/dhis-web-visualizer/scripts/core.js	2015-04-16 22:30:22 +0000
+++ dhis-2/dhis-web/dhis-web-apps/src/main/webapp/dhis-web-visualizer/scripts/core.js	2015-04-22 09:10:45 +0000
@@ -1370,6 +1370,10 @@
 			support.prototype.number.prettyPrint = function(number, separator) {
 				separator = separator || 'space';
 
+                if (!number) {
+                    return;
+                }
+
 				if (separator === 'none') {
 					return number;
 				}