GSSAPI Failure: gss_accept_sec_context

[The Shell <samwun@hgcbroadband.com>]

Dear all,

I m not sure whether this is ldap or SASL problem , so I sent to both 
mailing list.
The command I used to test is "ldapwhoami -Y GSSAPI."

I want to test the setup of OpenLdap (2.2.2b) with SASL. But it appeared 
as failed with the following error:
...............
ber_dump: buf=0x082b3c00 ptr=0x082b3e51 end=0x082b3e51 len=0
conn=1 op=0 BIND dn="" method=163
==> sasl_bind: dn="" mech=GSSAPI datalen=565
send_ldap_result: err=49 matched="" text="SASL(-13): authentication 
failure: GSSAPI Failure: gss_accept_sec_context"
conn=1 op=0 RESULT tag=97 err=49 text=SASL(-13): authentication failure: 
GSSAPI Failure: gss_accept_sec_context
daemon: activity on 1 descriptors
daemon: activity on: 14r
daemon: read activity on 14
connection_get(14)
daemon: removing 14

I turned on debug mode when starting slapd, so I got the above message 
shown on the console.
Where should I look into in order to troubleshoot the problem?

Thanks
sam