scheduler service

I'm trying to use the quartz scheduler service to schedule a model. It
seems from the documentation to be pretty straightforward, but I haven't
been able to get it to work. The logs show that the job has been
scheduled correctly and the next run time is correct:

INFO    2004-08-06 14:05:51.051   [svc-schedule-quartz]
(/org.keel.services.schedule.quartz.QuartzScheduler.scheduleCronJob(Quar
tzScheduler.java:214)): Scheduling Quartz job job-1 in group DEFAULT
INFO    2004-08-06 14:05:51.051   [svc-schedule-quartz]
(/org.keel.services.schedule.quartz.QuartzScheduler.scheduleCronJob(Quar
tzScheduler.java:249)): Scheduled Quartz job job-1, next:Fri Aug 06
14:06:00 PDT 2004, model:scheduler.refreshremedy-job, cron: 0 0/3 * * *
? *

But when that time comes, nothing happens at all. No error messages,
nothing in the logs, no execution of the job. I'm hoping I'm missing
something obvious that somebody can point out. Here's the model I'm
trying to execute, which is basically just taken from one of the quartz
service test classes. Is something wrong here?:

/**
 * @avalon.component
 * @avalon.service type=org.keel.services.model.Model
 * @x-avalon.info name=scheduler.refreshremedy-job
 * @x-avalon.lifestyle type=singleton
 */
public class RefreshRemedyJob  extends StandardLogEnabledModel
implements Schedulable{
		
	public ModelResponse execute(ModelRequest req) throws
ModelException {
		
		ModelResponse res = req.createResponse();
		log.info("Calling execute() method for Schedulable
interface");
		this.execute();
		return res;
	}
	
	public void execute(){
		
        log.info("Begin execution of model batch job");
		//Business logic goes here....
		log.info("Finished running model batch job");
	}	
}

Thanks,
Lou