JingleManager exception

I'm currently working at a smack project...we got to the point in wich we want to implement the voip part...the call is being made without any problem but when the other client receive the session this exception is being throw:

FATAL EXCEPTION: Smack-Incoming Processor 0 (0)                             

                                          java.lang.NullPointerException
                                                                            at org.jivesoftware.smackx.jingleold.JingleManager$3.accept(JingleManager.java:452 )
                                                                            at org.jivesoftware.smack.AbstractXMPPConnection$ListenerWrapper.filterMatches(Abs tractXMPPConnection.java:1242)
                                                                            at org.jivesoftware.smack.AbstractXMPPConnection.invokePacketCollectorsAndNotifyRe cvListeners(AbstractXMPPConnection.java:1094)
                                                                            at org.jivesoftware.smack.AbstractXMPPConnection$ListenerNotification.run(Abstract XMPPConnection.java:999)
                                                                            at org.jivesoftware.smack.util.BoundedThreadPoolExecutor$1.run(BoundedThreadPoolEx ecutor.java:48)
                                                                            at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
                                                                            at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
                                                                            at java.lang.Thread.run(Thread.java:856)

Is there any way to fix this problem?
Thanks in advance