I'm finding that the Koha instance's intranet site is crashing with an Internal Server Error. It first happened when I tried to change the superlibrarian's user ID. I couldn't recover the system at all, and had to delete and re-create the instance. It has recurred in the installer when selecting the language. Log files are being filled with repeated errors about missing database tables, e.g. indexer-output.log: DBD::mysql::st execute failed: Table 'koha_zilib.zebraqueue' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. DBD::mysql::st fetchrow_arrayref failed: fetch() without execute() at /usr/share/koha/lib/Koha/Database.pm line 152. DBD::mysql::st execute failed: Table 'koha_zilib.zebraqueue' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. DBD::mysql::st fetchrow_arrayref failed: fetch() without execute() at /usr/share/koha/lib/Koha/Database.pm line 152. plack-intranet-error.log: [2023/02/27 14:28:08] [WARN] DBD::mysql::st fetchrow_hashref failed: fetch() without execute() at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st execute failed: Table 'koha_zilib.language_descriptions' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st fetchrow_hashref failed: fetch() without execute() at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st execute failed: Table 'koha_zilib.language_descriptions' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st fetchrow_hashref failed: fetch() without execute() at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st execute failed: Table 'koha_zilib.systempreferences' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st execute failed: Table 'koha_zilib.systempreferences' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st execute failed: Table 'koha_zilib.systempreferences' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] DBD::mysql::st execute failed: Table 'koha_zilib.systempreferences' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. [2023/02/27 14:28:08] [WARN] Install required, redirecting to Installer at /usr/share/koha/lib/C4/Auth.pm line 762. plack-error.log: DBD::mysql::st execute failed: Table 'koha_zilib.systempreferences' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. DBD::mysql::st execute failed: Table 'koha_zilib.systempreferences' doesn't exist at /usr/share/koha/lib/Koha/Database.pm line 152. Template process failed: file error - /usr/share/koha/intranet/htdocs/intranet-tmpl/prog/en-GB/modules/installer/s tep1.tt: not found at /usr/share/koha/lib/C4/Templates.pm line 127. Template process failed: file error - /usr/share/koha/intranet/htdocs/intranet-tmpl/prog/en-GB/modules/installer/s tep1.tt: not found at /usr/share/koha/lib/C4/Templates.pm line 127. Any help appreciated.