What does "invalid new-expression of abstract class type 'class name' " mean?

I am busy with an assignment and am forced t use the factory method design pattern to create iterators which iterate over a container but I keep getting the above error. The classes I have are as follows:

ConstinerIterator.h:

#include "Object.h"

class ContainerIterator : public Object
{
public:
    void print(ostream& os);
    virtual Object* getFromIndex(int i) = 0;
protected:
    int compareTo(Object& obj);
};

DALIterator.h

#include "ContainerIterator.h"

class DALIterator : public ContainerIterator
{
public:
    DALIterator(Object** array)
    {
        this->array = array;
    }
    Object* getFromIndex(int i)
    {
        return array[i];
    }

private:
    Object** array;
};

ListAsArray.h:

#include "List.h"

class ListAsArray: public List
{
public:
    virtual ContainerIterator* createIterator() = 0;
};

DynamicArrayList.h

#include "ListAsArray.h"
#include "ArrayFactory.h"

class DynamicArrayList: public ListAsArray
{
public:
    DynamicArrayList()
    {
        array = new Object*[10];
    }
    ContainerIterator* createIterator()
    {
        IteratorFactory* factory = new ArrayFactory();
        return factory->factoryMethod(array);
    }

private:
    Object** array;
};

IteratorFactory.h

#include "Object.h"
#include "ContainerIterator.h"

class IteratorFactory : public Object
{
public:
    void print(ostream& os);
    virtual ContainerIterator* factoryMethod(Object** array) = 0;
protected:
    int compareTo(Object& obj);
};

ArrayFactory.h

#include "IteratorFactory.h"
#include "DALIterator.h"

class ArrayFactory : public IteratorFactory
{
public:
    ContainerIterator* factoryMethod(Object** array)
    {
        return new DALIterator(array);
    }
};

main.cpp:

#include <iostream>
#include "DynamicArrayList.h"
using namespace std;
int main()
{
    DynamicArrayList* dal = new DynamicArrayList();
    ContainerIterator* ci = dal->createIterator();

    return 0;
}

The error I get is:

ArrayFactory.h: In member function ‘virtual ContainerIterator* ArrayFactory::factoryMethod(Object**)’:
ArrayFactory.h:16:31: error: invalid new-expression of abstract class type ‘DALIterator’
   return new DALIterator(array);
                               ^
In file included from ArrayFactory.h:9:0,
                 from DynamicArrayList.h:5,
                 from DynamicArrayList.cpp:5:
DALIterator.h:10:7: note:   because the following virtual functions are pure within ‘DALIterator’:
 class DALIterator : public ContainerIterator

Thanks in advance for any help and apologies for the length of the question.