[Serusers] kphone work with ser.can NOT disconnect... ???

[dev2003 at mail.ustc.edu.cn]

kphone work with ser.can NOT disconnect.kphone is no respond
show KCallWidget: Starting force disconnect...
then kphone is no respond .
why? help me
# kphone
....
SipClient: Receiving message...
SipClient: Received: 15:26:25.776
---------------------------------
SIP/2.0 200 OK
Via: SIP/2.0/UDP 192.168.139.58;rport=15073;received=222.33.36.198
CSeq: 6935 BYE
To: "24800027" <sip:t1 at t1.com>;tag=e2tQMqJQRd42Gx0hev
From: "wxt" <sip:t2 at 51t1.com>;tag=7A3E61A4
Call-ID: cc8TxjEcMBWRed at 192.168.139.157
Server: VizufonSIP/0.2 (beta.EP.CNSTEC.Sep 15 2004)
Content-Length: 0


SipCall: Incoming response
SipCall: Checking for Contact and Record-Route
SipTransaction: Incoming Response
SipCallMember: localStatusUpdated: 200
KCallWidget: Starting force disconnect...