NetSuite generates errors to provide feedback to users of what and where went wrong. An error message usually specifies the script name, function type and the fact whether it is a custom form script or not.
Error: "nlapiLookupField: Missing a required argument: id"
This error ocurs because of missing mandatory argument "id" in the script. In this case, the error message is referring to nlapiLookupField() function and the 'id' parameter refers to the internal id of the record where the field being retrieved is located. Adding the required argument will resolve the issue.
For more information about the nlapiLookUpField API, go to SuiteAnswers article # 10254.