[Koha] search_for_data_inconsistencies.pl: Can't call method "get_column"

Hi We are using Koha 20.11.02 with MariaDB 10.3.39, running on Debian GNU/Linux 10. When calling the script "search_for_data_inconsistencies.pl" the only output is the following: $ sudo koha-shell -c "perl /usr/share/koha/bin/maintenance/search_for_data_inconsistencies.pl" instancename Can't call method "get_column" on an undefined value at /usr/share/koha/bin/maintenance/search_for_data_inconsistencies.pl line 157. Does anyone know how to solve this problem? Best wishes: Michael -- Geschäftsführer · Diplombibliothekar BBS, Informatiker eidg. Fachausweis Admin Kuhn GmbH · Pappelstrasse 20 · 4123 Allschwil · Schweiz T 0041 (0)61 261 55 61 · E mik@adminkuhn.ch · W www.adminkuhn.ch