=== modified file 'dhis-2/dhis-web/dhis-web-dataentry/src/main/webapp/dhis-web-dataentry/javascript/form.js'
--- dhis-2/dhis-web/dhis-web-dataentry/src/main/webapp/dhis-web-dataentry/javascript/form.js	2013-01-04 18:10:25 +0000
+++ dhis-2/dhis-web/dhis-web-dataentry/src/main/webapp/dhis-web-dataentry/javascript/form.js	2013-02-04 22:40:03 +0000
@@ -1974,7 +1974,7 @@
         var id = this.getDataValueIdentifier( dataElementId, categoryOptionComboId, periodId, organisationUnitId );
         var dataValues = this.getAllDataValues();
 
-        if ( dataValues[id] != null )
+        if ( dataValues != null && dataValues[id] != null )
         {
             delete dataValues[id];
             localStorage[KEY_DATAVALUES] = JSON.stringify( dataValues );