title: Property [] of class [] can not be null error in Grails
body: <p>I am new to Grails and getting this error on two out of my three domains when I run the project on all the domains content.  The domain the works is </p>
  
  <pre><code>class Location {
  
      def scaffold = true
  
  
      String company 
      String name 
      String address
      static belongsTo=[company:Company]
  
      static constraints = {
  
  }
  
  }
  </code></pre>
  
  <p>The domain that does not work is </p>
  
  <pre><code>class Report {
  
      def scaffold = true
  
      String   title
      String   location 
      Date     published
  
      static belongsTo=[location:Location]
  
      static constraints = {
  
  }
  }
  </code></pre>
  
  <p>I can not see the structural or syntax issue that is trowing the errors.  I have been trying a variety of adds and subtracts and can not seem to find anything that address this error at a basic level.  Again I have just started using Grails and Groovy</p>