The following error message:
java.lang.IllegalArgumentException
location cannot be empty for user:
sometimes occurs when lending staff are trying to action an In Process request sent by a non-RACER borrowing library via ISO.
The error is due to a patron ID in the request matching an existing patron ID in RACER.
OCLC staff can quickly resolve the problem by removing the patron ID which is not a required field on the lending side. If you come across this error please send the request numbers to RACER Support.