In your frontend I would do:

ProxyPass /bcdb/ http://localhost:8080/bcdb/
ProxyPassReverse /bcdb/ http://localhost:8080/bcdb/

and in the forum virtualhost:

ProxyPass /forum/ http://localhost:8080/forum/
ProxyPass /forum/ http://localhost:8080/forum/

and then in your backend:

Alias /bcdb/ /path/to/links-sql/
Alias /forum/ /path/to/gforum/
<Directory /path/to/links-sql/>
SetHandler perl-script
PerlHandler Apache::Registry
PerlSendHeader On
Options ExecCGI
</Directory>
<Directory /path/to/forum/>
.. same thing
</Directory>

That way you can keep it all on one port.

Cheers,

Alex
--
Gossamer Threads Inc.