Bug 123219 Export data in attached file which has a table covers multiple page will throw exception.
Description: Export data in attached file which has a table covers multiple page will throw exception. Steps to reproduce: 1. Preview attached design file in viewer. 2. Select the table and click Export Data Expected result: No errors. Actual result: Exception Exception in: ReportEngineService.getMetaData( )
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/DataExtractionTask.java
ReportItemDesign rptItem = (ReportItemDesign) report
				.getReportItemByID( instanceId.getComponentID( ) );
		assert rptItem != null;
		
		validateSelectedColumns( rptItem.getQuery( ) );
		
		
		DataID dataId = instanceId.getDataID();
		InstanceID instId = instanceId;
		while( instId != null && dataId == null ){
			instId = instId.getParentID( );
			if( instId != null )
			{
				dataId = instId.getDataID();
			}
		}
		
		if(dataId == null)
			return null;
		
		DataSetID dataSetId = dataId.getDataSetID( );
		assert dataSetId != null;
		
		String queryResultName = dataSetId.getDataSetName( );
		
		if( resultMetaList == null )
		{
			resultMetaList = new ArrayList( );
		}
		else