body fields update by transaction columns field in first line item

i am trying to set department, class, location on PO by line item custom fields values.
custom body field is working fine, but standard field is not as well can not add line item.

please help me.

function autopop(type){    if(type=='item'){        var lineAcc = nlapiGetCurrentLineItemValue('item','custcol_emp_account');   var lineDept = nlapiGetCurrentLineItemValue('item','custcol_po_department');   var lineLoc = nlapiGetCurrentLineItemValue('item','custcol_po_location');   var lineTech = nlapiGetCurrentLineItemValue('item','custcol_po_technology');    nlapiSetFieldValue('custbody_so_account',lineAcc, true, false);  nlapiSetFieldValue('department',lineDept);  nlapiSetFieldValue('location',lineLoc);  nlapiSetFieldValue('class',lineTech);            }    return true;  }