I am getting following error. Can someone tell me what am I missing?

Challenge Not yet complete... here's what's wrong: 
There was an unexpected error in your org which is preventing this assessment check from completing: System.DmlException: Insert failed. First exception on row 0; first error: FIELD_INTEGRITY_EXCEPTION, field integrity exception: []
 

/**
 * @name TestDataFactory
 * @description Contains methods to construct and/or validate commonly used records
**/
public with sharing class TestDataFactory {

     private static final Id STANDARD_PRICEBOOK_ID = (Test.isRunningTest())
            ? Test.getStandardPricebookId()
            : [SELECT id FROM PriceBook2 WHERE isStandard = true LIMIT 1].id;
    /**
     * @name ConstructCollaborationGroup
     * @description
    **/
    public static CollaborationGroup ConstructCollaborationGroup(){
        
        CollaborationGroup collabGroup = new CollaborationGroup();
        collabGroup.Name='Test'+Constants.INVENTORY_ANNOUNCEMENTS;
        collabGroup.CollaborationType='Public'; //can be 'Public' or 'Private'                   
        return collabGroup;
    }

    /**
     * @name CreateProducts
     * @description Constructs a list of Product2 records for unit tests
    **/
    public static List<Product2> ConstructProducts(Integer cnt){
        
        List<Product2> productList=new List<Product2>();
		list<Schema.PicklistEntry> pEntries = Constants.PRODUCT_FAMILY;
        Integer j=0;
        for(Integer i=0;i<cnt;i++){
                Product2 prod=new Product2(name='testProd'+i,
                                           IsActive=true,
                                          Initial_Inventory__c=10);
            if(j==4){
                j=0;
            }
            prod.Family=pEntries.get(j).getValue();
            j++;
            productList.add(prod); 
        }
        return productList;
    }

    /**
     * @name CreatePricebookEntries
     * @description Constructs a list of PricebookEntry records for unit tests
    **/
    public static List<PriceBookEntry> ConstructPricebookEntries(List<Product2> prods){
      
        List<PriceBookEntry> priceBokkList=new List<PriceBookEntry>();
		system.debug('STANDARD_PRICEBOOK_ID'+STANDARD_PRICEBOOK_ID);
        for(Product2 prod:prods){
            PriceBookEntry pbe=new PriceBookEntry();
            pbe.product2Id=prod.id;
            pbe.Pricebook2Id=STANDARD_PRICEBOOK_ID;
            pbe.isActive=true;
            pbe.UseStandardPrice=true;
            pbe.UnitPrice=10;
			priceBokkList.add(pbe);            
        }
        return priceBokkList;
    }

    /**
     * @name CreateAccounts
     * @description Constructs a list of Account records for unit tests
    **/
    public static List<Account> ConstructAccounts(Integer cnt){
        
        List<Account>acclist=new List<Account>();
        for(integer i=0;i<cnt;i++){
            Account acc=new Account(name='test'+i);
            acclist.add(acc);
        }

        return acclist;
    }

    /**
     * @name CreateContacts
     * @description Constructs a list of Contacxt records for unit tests
    **/
    public static List<Contact> ConstructContacts(Integer cnt, List<Account> accts){
       
        List<Contact> contactlist=new List<Contact>();
            for(integer i=0;i<cnt;i++){
                Contact con=new Contact(lastname='TestContact'+i,AccountId=accts.get(i).id);
                contactlist.add(con);
            }
        return contactlist;
    }

    /**
     * @name CreateOrders
     * @description Constructs a list of Order records for unit tests
    **/
    public static List<Order> ConstructOrders(Integer cnt, List<Account> accts){
        
        List<Order> orderList =new List<Order>();
        for(Integer i=0;i<cnt;i++){
                Order orderObj=new Order();
            	orderObj.Name='order'+i;
                orderObj.AccountId=accts.get(i).id;
                orderObj.Status=Constants.DRAFT_ORDER_STATUS;
                orderObj.EffectiveDate=system.today();
                orderList.add(orderObj);
        }
        return orderList;
    }

    /**
     * @name CreateOrderItems
     * @description Constructs a list of OrderItem records for unit tests
    **/
    public static List<OrderItem> ConstructOrderItems(integer cnt, list<pricebookentry> pbes, list<order> ords){
        
        List<OrderItem> orderItems = new List<OrderItem>();
        for(Integer i=0;i<cnt;i++){
            OrderItem item=new OrderItem();
            item.orderId=ords.get(i).id;
            item.PricebookEntryId=pbes.get(i).id;
            item.Quantity = Constants.DEFAULT_ROWS;
            item.UnitPrice = 1;
            orderItems.add(item);
        }
        return orderItems;
    }

    /**
     * @name SetupTestData
     * @description Inserts accounts, contacts, Products, PricebookEntries, Orders, and OrderItems.
    **/
    public static void InsertTestData(Integer cnt){
       
        list<Account> accounts = ConstructAccounts(cnt);
        Insert accounts;
        
        list<Contact> contacts = ConstructContacts(cnt, accounts);
        insert contacts;
        
        list<Product2> products= ConstructProducts(cnt);
        insert products;

        list<PriceBookEntry> entries = ConstructPricebookEntries(products);
        insert entries;
        
        list<Order> orders = ConstructOrders(cnt, accounts);
        insert orders;
        
        list<OrderItem> orderItems = ConstructOrderItems(cnt, entries, orders);
        insert orderItems;
            
    }

}

 

I can't progress pass the first stage on this project.  I get the error: Could not authenticate with the IBM Bluemix service. Please validate your credentials (also below).  Please can anyone help?