Unexpected Error on Before Load Sublist

Hi,

I'm trying to add a sublist to the customer page via a before load script. I've created a tab and and the sublist and checked and confirmed that the script is running through my search results properly (and the search isn't returning anything too long to time out).

I've also gone through and added nlapiLogExecution lines to confirm the script isn't getting hung up at any particular line. However now on loading the customer record I'm getting an unexpected error. Can anyone spot anything wrong with what I've written:

        var projectTab = form.addTab('custpage_projectschedule','Project Schedule');          var itemList = form.addSubList('custpage_projectitemlist','list','Item List',projectTab);            nlapiLogExecution('debug','Details','salesorderItemSearch.length = ' + salesorderItemSearch.length)          itemList.addField('itemordered','text','Item Ordered');          itemList.addField('quantityordered','text','Quantity');          itemList.addField('quantityshipped','text','Quantity Shipped')          itemList.addField('frompurchaseorder','text','Purchase Order');            for(var i = 0; i < salesorderItemSearch.length; i++){              var itemId = salesorderItemSearch[i].getValue('item');              var itemName = nlapiLookupField('inventoryitem',itemId, 'name');              itemList.setLineItemValue('itemordered',i+1,itemName);              itemList.setLineItemValue('quantityordered',i+1,salesorderItemSearch[i].getValue('quantity'));              itemList.setLineItemValue('quantityshipped',i+1,salesorderItemSearch[i].getValue('quantityshiprecv'));              var poId = salesorderItemSearch[i].getValue('applyingtransaction');              var poName = nlapiLookupField('purchaseorder',poId,'tranid');              itemList.setLineItemValue('frompurchaseorder',i+1,poName);          }