kerberos developping help

[CD000 Albert Shen]

    Now I'm do some developping of kerberos protocol. But I meet a problem which make me confused. I use a RH9 kdc server and program my own client peer. I succeed in AS-REQ and AS-REP analization. But when I send TGS-REQ to the KDC, it give me an ERROR reply. The e-code is "KRB_AP_ERR_SKEW" and the ctime is "1970-01-01 10:25:14".
     It is so strange that my computer show the correct time, and each time I receive the ERROR response I get the same ctime even in seconds. I'm grateful if who can help me, thanks!
 
 
 
                                                                                                             best regards!
                                                                                                              2004-07-18