Following up, In Koha 3.2-5 it appears that callnumber.pl does not work without a simple fix. I had to add the following line at the top of the file to work around it. use C4::Auth qw(get_template_and_user); An error was reported in the koha-error_log indicating that get_template_and_user was not defined. Also, it was hard to debug our customized callnumber.pl callback (value_builder). I was able to add print statements that would print in context (in the field I was trying to add the callback for). print "Content-type: text/html\n\n"; print ... (This redirects whatever you print to the field. Sometimes error messages also appear). I hope this helps someone, Pete. -- View this message in context: http://koha.1045719.n5.nabble.com/callnumber-pl-errors-in-koha-error-log-tp3... Sent from the Koha - Discuss mailing list archive at Nabble.com.