Bug 135790 ClassCastException in RowData.
ClassCastException is thrown in RowData line 81(IBaseExpression expr = ( IBaseExpression ) valueExpressions.get( index - 1 );).
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/TableItemExecutor.java
{
			assert cellEmitter != null;
			return cellEmitter;
		}
		public void flush( )
		{
			int rowCount = layout.getRowCount( );
			int colCount = layout.getColCount( );
			for ( int i = 0; i < rowCount; i++ )
			{
				Row row = layout.getRow( i );
				IRowContent rowContent = ( IRowContent ) row.getContent( );
				emitter.startRow( rowContent );
				for ( int j = 0; j < colCount; j++ )
				{
					Cell cell = row.getCell( j );
					if ( cell.getStatus( ) == Cell.CELL_USED )
					{
						CellContent content = ( CellContent ) cell.getContent( );
						content.cell.setColumn( cell.getColId( ) );
						content.cell.setRowSpan( cell.getRowSpan( ) );
						content.cell.setColSpan( cell.getColSpan( ) );
						emitter.startCell( content.cell );
						if ( content.buffer != null )
						{
							content.buffer.flush( );
						}
						emitter.endCell( content.cell );
					}
					if ( cell.getStatus( ) == Cell.CELL_EMPTY )