Bug 121687 Exception throws when export data in table which inside a grid cell.
Description: Exception throws when export data in table which inside a grid cell. Steps to reproduce: 1. insert a grid. 2. insert one table to one grid cell. 3. insert another table to the other grid cell. 4. export data in two tables. Expected result: Data are exported. Actual result: Exception in: ReportEngineService.getMetaData( )
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/ir/Report.java
* set the report's page setup
	 * 
	 * @param pageSetup
	 *            page setup
	 */
	public void setPageSetup( PageSetupDesign pageSetup )
	{
		this.pageSetup = pageSetup;
	}
	/**
	 * get the report's page setup
	 * 
	 * @return page setup of this report
	 */
	public PageSetupDesign getPageSetup( )
	{
		return this.pageSetup;
	}
	/**
	 * get total contents.
	 * 
	 * @return sections in the report body.
	 */
	public ArrayList getContents( )
	{
		return this.contents;
	}
	/**
	 * get contents count in a report.
	 *