Does the manage domains page of the dreamhost panel have an entry for that domain? It must also say "fully hosted" in the web hosting column. I suspect you haven't added it there yet.
Once you've done that, and DNS has propagated, the browser error should be gone. Also when you add the domain as fully hosted, the happy dreamhost robot will create a directory on the server in your home directory (ftp root) named 0502539468.com that is the directory you files go in.
Here's a great wiki article on moving a Wordpress site to dreamhost http://wiki.dreamhost.com/Move_WordPress_to_DreamHost
And another wiki page that should help find the topics you need http://wiki.dreamhost.com/Getting_Started_topics