OQL fails when queryiong nested objects

My object structure is as below:

Class A

{

   public string key;

   public string fieldName;

   List<ArrayList<MyCustomObject>> myNewObject = new ArrayList<ArrayList<MyCustomObject>>();

}

Class MyCustomObject

{

public String key;

public String value

}

Now I want to write a OQL on this object. But i get a result undefined when I write query as:

Select * from /ExampleRegion er, er.myNewObject

Exception is: Unknown Result Type .

Same query works if my Object structure has only one list<Object>: i.e.

Class A

{

   public string key;

   public string fieldName;

   List<MyCustomObject> myNewObject = new ArrayList<MyCustomObject>();

}

Select * from /ExampleRegion er, er.myNewObject -- will work perfectly.

Any solution to this issue. Am I doing somethign wrong?