Bug 208419 NullPointerException at CubeResultSet close
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/data/dte/DataInteractiveEngine.java
resultSet = new QueryResultSet( this, context,
							query,
							(IQueryResults) dteResults );
			}
			else
			{
				if ( parentResult instanceof QueryResultSet )
				{
					pRsetId = ( (QueryResultSet) parentResult )
							.getQueryResultsID( );
				}
				else
				{
					pRsetId = ( (CubeResultSet) parentResult )
							.getQueryResultsID( );
				}
				rowId = parentResult.getRawID( );
				
				
				
				if ( useCache )
				{
					dteResults = getCachedQueryResult( query );
				}
				if ( dteResults == null )
				{
					dteResults = dteSession.execute( pQuery, parentQueryResults, scope );
					if ( query.cacheQueryResults( ) )
					{
						cachedQueryToResults.put( query, dteResults.getID( ) );