The game is temporarily closed, but it will return some time in the second half of March.
Sun(David) discovered a dangerous hole in the security due to the original Barp code and fixing it would require a lot of time and could hurt performance. Therefore the game will be down while Sun develops new code from scratch. When the game reopens it will only be a chat, with many more features than the current chat has. Over time a new game engine will be built up around the chat.
The forum at http://www.castellumonline.com/forum will remain online and active, so you can keep in touch with others and keep up with the news there. You can also follow Sun's Twitter account http://twitter.com/davidrg86 to keep up with progress.