What's error code "ka 10" mean?

[zxg]

Hi, Folks:

        Does anyone there know what error code ka 10 means? I got it when
sending a packet to kaserver to ask for krbtgt. The responding message 
contains "code = 180490: Unknown code ka 10 ( 1804". I am quite confused 
because I can use the same program with mit kerberos server without problem.
And I believe there is none business here with string_to_key. Any suggestion?

-jason