I am running a SIP application on the S60 3rd Edition emulator and I keep getting a java AbstractMethodError on the response (180) to the SIP Invite.

I have basically one class that implements SipClientConnectionListener, SipServerConnectionListener and sends the INVITE. It sets itself as the listener for any incoming requests as well as the listener for incoming reponses - it thus implements both notifyRequest and notifyResponse.

the INVITE request goes out fine, I can see the 180 Response in ethereal but the code fails on receiving the response, any idea why

Uncaught exception: java.lang.Error: AbstractMethodError
- com.ibm.icm.sip.DeviceSipClient.notifyResponse(), bci=0
- com.symbian.midp.io.protocol.sip.SipClientConnectionImpl$NotifyResponseExecutor.execute(), bci=8
- com.symbian.midp.io.protocol.sip.NotificationExecutor.run(), bci=36
- java.lang.Thread.run(), bci=11