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
prepareMetaData( );
		
		resultSetName = (String)mapDispNameToResultSetName.get( displayName );
		selectedColumns = null;
		currentResult = null;
	}
	
	public List getMetaData( ) throws EngineException
	{
		if ( resultMetaList == null )
		{
			resultMetaList = new ArrayList( );
			ResultMetaData metaData = null;
			if ( selectedColumns == null && instanceId != null )
			{
				currentResult = extract( );
				try
				{
					resultMetaList.add( currentResult.getResultMetaData( ) );
				}
				catch( BirtException be )
				{
					be.printStackTrace();
				}
			}
			
			if( selectedColumns == null )
			{
				return null;
			}