I get the same error
0 DB_ERROR_NOT_CONNECTED
in:
[select * from xxxxxxproject_version WHERE project_version_key = 'Zen-Cart Database' ]

My configure file are both correct.checked phpmyadmin everything looks good..of what I know.

Moved my zen db to a new host.
was mediatemple - did the one click install
(know anything about private installation loader for your Zen Cart)
now cpanel
any ideas on this
Thanks