how to get a flexfield information from item via groovy script

Summary:

Hi, we try to get a eff information from item via groovy script, but the we did the error in attached

Content (please ensure you mask any confidential information):

import oracle.apps.scm.doo.common.extensions.ValidationException;

import oracle.apps.scm.doo.common.extensions.Message;

def lines = header.getAttribute("Lines");

String businessUnit = header.getAttribute("BusinessUnitName");

String orderTypeCode = header.getAttribute("TransactionTypeCode");

while(lines.hasNext()) 

{

def line = lines.next();

def inventoryItemId = line.getAttribute("ProductIdentifier");

def orgId = line.getAttribute("InventoryOrganizationIdentifier");

def item = getItem(inventoryItemId , orgId);

def itemEff = getEffItem(inventoryItemId , orgId);

String itemCategory = itemEff.getAttribute("nttitemCategorySubCat");

def lines1 = txnLookupPVO.findByViewCriteria(vc2, -1);

while (lines1.hasNext())