=== modified file 'dhis-2/dhis-services/dhis-service-dxf2/src/main/java/org/hisp/dhis/dxf2/datavalueset/DefaultDataValueSetService.java'
--- dhis-2/dhis-services/dhis-service-dxf2/src/main/java/org/hisp/dhis/dxf2/datavalueset/DefaultDataValueSetService.java	2013-10-22 14:32:09 +0000
+++ dhis-2/dhis-services/dhis-service-dxf2/src/main/java/org/hisp/dhis/dxf2/datavalueset/DefaultDataValueSetService.java	2013-12-08 21:46:50 +0000
@@ -168,6 +168,11 @@
     {
         Set<Period> periods = new HashSet<Period>( periodService.getPeriodsBetweenDates( startDate, endDate ) );
 
+        if ( periods.isEmpty() )
+        {
+            throw new IllegalArgumentException( "At least one period must be specified" );
+        }
+                
         dataValueSetStore.writeDataValueSetXml( null, null, null, null, getDataElements( dataSets ), periods, getOrgUnits( orgUnits ), out );
     }
 
@@ -175,6 +180,11 @@
     {
         Set<Period> periods = new HashSet<Period>( periodService.getPeriodsBetweenDates( startDate, endDate ) );
 
+        if ( periods.isEmpty() )
+        {
+            throw new IllegalArgumentException( "At least one period must be specified" );
+        }
+                
         dataValueSetStore.writeDataValueSetCsv( getDataElements( dataSets ), periods, getOrgUnits( orgUnits ), writer );
     }
 

=== modified file 'dhis-2/dhis-web/dhis-web-importexport/src/main/java/org/hisp/dhis/importexport/action/datavalue/ExportDataValueAction.java'
--- dhis-2/dhis-web/dhis-web-importexport/src/main/java/org/hisp/dhis/importexport/action/datavalue/ExportDataValueAction.java	2013-08-23 16:05:01 +0000
+++ dhis-2/dhis-web/dhis-web-importexport/src/main/java/org/hisp/dhis/importexport/action/datavalue/ExportDataValueAction.java	2013-12-08 21:46:50 +0000
@@ -114,6 +114,8 @@
     public String execute()
         throws Exception
     {
+        //TODO reimplement to use web api
+        
         Set<String> orgUnits = new HashSet<String>();
         
         for ( OrganisationUnit unit : selectionTreeManager.getReloadedSelectedOrganisationUnits() )