[Koha] Net::Z3950 module

Anybody here have any experience with the perl Net::Z3950 module? I've got it doing successful searches of the National Library of Canada, but I can't figure out how to get raw MARC results out of it. I can get GRS1 results, or structured text results no problem, but I can't get MARC for some reason. When I use: print Net::Z3950::Record::USMARC::render($rec); I get the following error: Can't call method "output" on an undefined value at /usr/local/lib/site_perl/i386-linux/Net/Z3950/Record.pm line 236. Steve.