Cannot update Location on Fulfullment

Hi all,

I have a 'pageInit' client script running when you at first create an Item Fulfillment from the 'fulfill' button on a Sales Order.

The Script starts, and I need it to manually set the location of each item in the list, the code looks as below.

   for(var i=1;i<=nlapiGetLineItemCount('item');i++) {    nlapiSelectLineItem('item',i);        postLog('Location for line '+i+' is '+nlapiGetLineItemValue('item','location'));        nlapiSetCurrentLineItemValue('item','location',100);      postLog('New Location for line '+i+' is '+nlapiGetLineItemValue('item','location'));      //done    nlapiCommitLineItem('item');    }   

The log lines I get are:

   Location for line 1 is null  TypeError: fld is undefined message=fld is undefined