"- About DB, I think Oracle is too much expensive for us. I think PostGreeSQL would be our choice. Is it all right?"
PostGreSQL and Oracle are supported about equally by OpenACS.
"- It would be an multi-language space."
OpenACS 5.0, currently in Alpha, has i18n support, both for content (identifying different versions of the same thing in different languages; native UNICODE storage) and for the web applications (UI can be changed to German, etc). Not all of the localization is complete. but anyone can contribute translations. You can see the work in progress at http://translate.openacs.org
