Problem running java on V5R2M0

Hello,
a working application on V4R5M0 and V5R1M0 do not work on V5R2M0 with the 
latest jt400.jar (runs on the QSH env.).
JDK is 1.3.
The latest PTF's cum. is installed.
When trying to connect a service (dtaq) following error is thrown:

A connection with a remote socket was reset by that socket.                     
                                          
java.net.SocketException: A connection with a remote socket was reset by that 
socket.                                     
      java/lang/Throwable.<init>(Ljava/lang/String;)V+4 (Throwable.java:90)     
                                          
      java/lang/Exception.<init>(Ljava/lang/String;)V+1 (Exception.java:38)     
                                          
      java/io/IOException.<init>(Ljava/lang/String;)V+1 (IOException.java:43)   
                                          
      java/net/SocketException.<init>(Ljava/lang/String;)V+1 
(SocketException.java:32)                                    
      java/net/SocketInputStream.read([BII)I+15 (SocketInputStream.java:86)     
                                          
      
com/ibm/as400/access/DataStream.readFromStream(Ljava/io/InputStream;[BII)I+0 
(DataStream.java:44)                   
      
com/ibm/as400/access/SignonExchangeAttributeRep.read(Ljava/io/InputStream;)V+0 
(SignonExchangeAttributeRep.java:79) 
      com/ibm/as400/access/AS400ImplRemote.signonConnect()V+0 
(AS400ImplRemote.java:1869)     

Thanks in advance for help.

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Franco Biaggi
CH-6807 Taverne