[Koha] koha-z3950-responder can't locate perl5db.pl

[Mark Alexander]

I've done a fresh install of Koha 25.05 on Ubuntu 24.04 server.
I'm now trying to get the z3950-responder to start so that
I can have Z39.50 server that puts out a 952$k with the item
status.  In the past I installed my own cobbled-together
z3950 responder server to do this, but I'd like to do it
without custom cruft.

So I did the expected things:

koha-z3950-responder --enable INSTANCE

Edit /etc/koha/sites/INSTANCE/z3950/config.xml, and uncomment this line:

      <z3950_responder_options>\-\-add-item-status k -t 5</z3950_responder_options>

Then start the responder:

koha-z3950-responder --start --debugger INSTANCE

I get this error:

 * Starting Z39.50/SRU daemon for rpl                                                                         Can't locate /perl5db.pl.
BEGIN failed--compilation aborted.

I see the missing file here:

/usr/share/perl/5.38.2/perl5db.pl

I also tried this within a koha-shell INSTANCE and got the same error.

Do I need to fiddle with the PERL5LIB environment variable?
What am I doing wrong?

-- 
By trying very hard to improve things, I am often able
to make them much worse. --Ashleigh Brilliant