Further to my original posting, the lookup failures all have entries in the z3950-daemon-xxxxx.log that have the following form: Processing isbn="0310250641" at 1 z3950.loc.gov:7090 voyager (1 forks) Q: @attr 1=7 "0310250641" ERROR: Can't call method "option" on an undefined value at /var/www/library/koha/intranet/scripts/z3950daemon/processz3950queue line 163, <KC> line 22. z3950.loc.gov:7090 done. What is this trying to tell me?