Hi Alfonso,
How many clients are you talking about? I'm guessing that you're overloading the ability of the ServerSocket to respond to connection requests. Once the server has used up the maximum number of worker threads, which defaults to 300, it won't accept any more connections. You can increase the number of worker threads by adding, say, "maxPoolSize=500" to the InvokerLocator.
Also, the default value for the ServerSocket backlog parameter is 200. You could try increasing it by adding "backlog=300", for example, to the InvokerLocator.
-Ron