Java Database Connectivity (JDBC)

hello, im having this weird error after executing this code:

Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver");
String url = "jdbc:sqlserver://localhost:1884;databaseName=Factura";
Connection conn = DriverManager.getConnection(url,"sa","1");

error:

Dec 13, 2010 1:06:51 AM com.microsoft.sqlserver.jdbc.SQLServerConnection Prelogin
WARNING: ConnectionID:1 Prelogin error: host localhost port 1884 Unexpected end of prelogin response after 0 bytes read
Dec 13, 2010 1:06:51 AM com.microsoft.sqlserver.jdbc.SQLServerConnection Prelogin
WARNING: ConnectionID:1 Prelogin error: host localhost port 1884 Unexpected end of prelogin response after 0 bytes read

what this means and how do i solve it?

thanks.