Troubling creating fulfillment record

USER_ERROR: You must enter at least one line item for this transaction.

Here is the code that I'm using:

//  transform the sales order into a fulfillment  var fulfillment = nlapiTransformRecord(REC_IDS.SO, salesOrder.getId(), REC_IDS.FULFILLMENT);    //  set the quantity for the line items  var lineCount = fulfillment.getLineItemCount('item');  this.AddTrace('Found ' + lineCount + ' line items on this fulfillment');  for(var i = 1; i <= lineCount; i++)  {      fulfillment.setLineItemValue('item', 'quantity', i, 1);  }    //  submit the record  var fulfillmentID = nlapiSubmitRecord(fulfillment, false);

From the UI, if I enter a 1 in the quantity field for my single line item it will let me save it.  It seems that in the code above this is what I'm doing, but I'm still getting the same error.