[Koha] "Internal Server Error" after installing Koha -- Database has no tables

[Ryan W]

Hello,

I am seeing "Internal Server Error" in my browser after installing Koha
locally. I see the error both when I visit the public interface and the
staff interface.

I followed the steps for installing Koha on Debian/Ubuntu:
https://wiki.koha-community.org/wiki/Koha_on_Debian

I have also looked at "How to set up a domain name for Koha":
https://wiki.koha-community.org/wiki/How_to_set_up_a_domain_name_for_Koha

In the plack-error.log I see some entries that suggest tables are missing:
C4::Languages::language_get_description(): DBI Exception: DBD::mysql::st
execute failed: Table 'koha_demo.language_descriptions' doesn't exist at
/usr/share/koha/lib/C4/Languages.pm line 363

I presume these tables will be created by the web installer, once I can get
to the web installer.  But the 500 error prevents me from accessing the web
installer.  Or am I wrong that the web installer creates the db tables?
Should the tables have been created when I ran...

koha-create --create-db demo


Thank you,
Ryan