Forums / Cotonti / Support / Internationalization rewrite url problem

First, about admin URL problem: admin, login and message are special, they don't understand rewrite parameters which normally go through index.php. So try linking to them without extra parameters like language.

Next, structure. Welcome from Genoa :) In Siena i18n is handled differently. You don't need to maintain similar structure for several languages in parallel, instead you create 1 structure tree in your primary language and then translate it to secondary languages. See this help for the start.