Very similarly I am getting the following while running setup for Alpha5.

Error: GT::SQL::Creator (42677): Circular reference detected in the foreign key schema. at Links/SQL.pm line 127.

Stack Trace
======================================
Links (42677): Links::environment called at Links.pm line 375.
Links (42677): Links::fatal called at GT/Base.pm line 261.
Links (42677): GT::Base::error_handler called at GT/Base.pm line 214.
Links (42677): GT::Base::error called at GT/SQL/Table.pm line 1272.
Links (42677): GT::SQL::Table::_circularity_check called at GT/SQL/Table.pm line 1284.
Links (42677): GT::SQL::Table::_circularity_check called at GT/SQL/Table.pm line 600.
Links (42677): GT::SQL::Table::check_schema called at GT/SQL/Creator.pm line 69.
Links (42677): GT::SQL::Creator::create called at Links/SQL.pm line 127.
Links (42677): Links::SQL::tables called at /sites/http/nextgen.ionus.com/docs/cgi/lsql/admin/setup.cgi line 248.
Links (42677): main::init_setup called at /sites/http/nextgen.ionus.com/docs/cgi/lsql/admin/setup.cgi line 43.
Links (42677): main::main called at /sites/http/nextgen.ionus.com/docs/cgi/lsql/admin/setup.cgi line 20.

Wil Hatfield
-ionUS.com
whatfield@ionus.com