Grails Validate Date error -

i new grails , going through ebook's examples. stuck trying define constraint on startdate cannot date in past. book had add this:

class race { static constraints = { // ... startdate(validator: {return (it > new date())}) // ... } 

doing causes errors thrown when go load create race page. compiles fine , server starts. book using older version of grails , running 2.1.0. ideas how can fix this?