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/parser/EngineIRVisitor.java
String name = propHandle.getDefn( ).getName( );
				Object value = propHandle.getValue( );
				assert name != null;
				assert value != null;
				Map properties = element.getCustomProperties( );
				assert properties != null;
				properties.put( name, value );
			}
		}
		
		setupNamedExpressions( handle, 
				element.getNamedExpressions( ) );
	}
	protected Expression createExpression( String expr )
	{
		if ( expr != null )
		{
			return new Expression( expr );
		}
		return null;
	}
	/**
	 * create a Action.
	 * 
	 * @param handle
	 *            action in DE
	 * @return action in Engine.
	 */
	protected ActionDesign createAction( ActionHandle handle )
	{