Bug 178489 [Deployment]Error log isn't printed in log file when using framset set method[0601]
engine/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/api/impl/RenderTask.java
this.offset = reportDoc.getInstanceOffset( iid );
			if ( offset == -1 )
			{
				throw new EngineException(
					"Invalid instance id :" + iid ); 
			}
		}
		ReportletRender( String bookmark ) throws EngineException
		{
			this.offset = reportDoc.getBookmarkOffset( bookmark );
			if ( offset == -1 )
			{
				throw new EngineException(
					"Invalid bookmark :" + bookmark ); 
			}
		}
		protected IReportExecutor createReader( )
		{
			return new ReportletReader( executionContext, offset );
		}
		protected void load( ReportContentLoader loader, IContentEmitter emitter )
		{
			loader.loadReportlet( offset, emitter );
		}
	}
	public void setInstanceID( String iid ) throws EngineException
	{
		setInstanceID( InstanceID.parse( iid ) );
	}
}