=== modified file 'dhis-2/dhis-api/src/main/java/org/hisp/dhis/common/adapter/GridRowsXmlAdapter.java'
--- dhis-2/dhis-api/src/main/java/org/hisp/dhis/common/adapter/GridRowsXmlAdapter.java	2011-12-14 15:54:36 +0000
+++ dhis-2/dhis-api/src/main/java/org/hisp/dhis/common/adapter/GridRowsXmlAdapter.java	2011-12-14 16:00:57 +0000
@@ -55,7 +55,7 @@
 
             for ( Object object : row )
             {
-                gridRow.getRowData().add( object != null ? object.toString() : null );
+                gridRow.getRowData().add( object != null ? object.toString() : "" );
             }
 
             gridRows.getRows().add( gridRow );