Reading input from servlet works in Windows but not Kubuntu

Question

I'm working on an applet/servlet/mysql database application and recently switched from Windows Vista (yeah, yeah) to Kubuntu Gutsy Gibbon. In Vista, everything worked fine (bet you've never heard anyone say that before), but in Kubuntu, I get a FileNotFound exception at the line where I initialize the ObjectInputStream (the ObjectOutputStream line doesn't throw an exception, but it doesn't look like that one works either (I output queries and such to the log files when the servlet receives them, but the logs are empty)). I tried everything I could think of (tomcat is fine, the servlet is where it should be, etc), but nothing seems to work.
Here's the code from my applet:
//open the connection to the servlet
URLConnection servletConnection = servletLocation.openConnection();
//inform the connection that we will send output and accept input
servletConnection.setDoOutput(true);
servletConnection.setDoInput(true);
//don't use a cached version of URL connection.
servletConnection.setUseCaches(false);
servletConnection.setDefaultUseCaches(false);
//we will send java serialized objects
servletConnection.setRequestProperty("Content-Type", "application/x-java-serialized-object");
//send the object to the servlet using serialization
//*THIS LINE DOESN'T THROW AN EXCEPTION*/
ObjectOutputStream output=new ObjectOutputStream(servletConnection.getOutputStream());
//serialize the object
output.writeObject(data);
output.flush();     
output.close();
//get the object input stream and receive a vector
/*THIS LINE THROWS A FILENOTFOUND EXCEPTION*/
ObjectInputStream input=new ObjectInputStream(servletConnection.getInputStream());               
thing = input.readObject();
input.close();
As you can see, I use the same servletConnection for both the output as well as the input. I don't know why one would work and not the other.
Any input would be great. Just to reiterate, it worked fine in Vista. I'm boggled.
Thanks.

Answer 1

If its a sand box restriction you should get a security restriction. How ever getting a FileNotFountException in an applet means that your code try to access a local file some ware which is not allowed in an applet unless it is signed.
Give us the code that you use to create the URL object. You should not use hard coded URLs in an applet. You have to get the Document URL or Codebase URL of applet and then modify it to derive the URL of the servlet.