I don't use aldiko, but the configuration below works with FBReader and Calibre Companion.
It is slightly edited to remove personal information. It uses a port (9191) rather than a named virtual host. The port calibre is listening on (9192) is blocked. It uses digest authentication to avoid passing clear-text passwords around, which you should also use unless you intend to use SSL or aldiko doesn't support it.
Code:
<VirtualHost *:9191>
<Location "/">
AuthType Digest
AuthName "******************"
AuthDigestDomain /
AuthDigestProvider file
AuthUserFile *****/library_digest_pw.txt
Require valid-user
</Location>
RewriteEngine on
RewriteRule ^(.*) http://127.0.0.1:9192/$1 [proxy]
SetEnv force-proxy-request-1.0 1
SetEnv proxy-nokeepalive 1
</VirtualHost>
BTW: why are you using the root page with aldiko? Shouldn't you be using
http://calibre.../opds ? There is no javascript in the opds version, and I would be surprised if aldiko knows how to deal with it.