I have asked the Romanian Postal Office for a list of postal codes in October 2006.
Here the answer :
As an answer to your question sent on www.posta-romana.ro, we inform that we can not provide a file of the postal codes of Romania. You can buy from Romanian Post Offices the CD with postal codes or can sign a contract with Romanian Post for Postal Codes data base (the price 1000 USD without taxes).
I fear as long as we don't find another provider we will not be able to include Romanian Postal codes in our database. You can buy it and include it in your copy of the GeoNames database. The GeoNames cc-by licence allows this.