samba - Sep 2008 - testjoin fails, but join works

Has anyone ever seen this condition before?  net rpc testjoin fails, but 
net rpc join succeeds.  Running samba 3.0.32 on CentOS 5.2:

[root@ocm samba]# net rpc testjoin -S ROARK -D ADMIN -U awilliam
Password:
[2008/09/16 08:44:27, 0] 
rpc_client/cli_pipe.c:get_schannel_session_key_common(2445)
  get_schannel_session_key: could not fetch trust account password for 
domain 'ADMIN'
[2008/09/16 08:44:27, 0] utils/net_rpc_join.c:net_rpc_join_ok(81)
  net_rpc_join_ok: failed to get schannel session key from server ROARK 
for domain ADMIN. Error was NT_STATUS_CANT_ACCESS_DOMAIN_INFO
Join to domain 'ADMIN' is not valid
[root@ocm samba]# net rpc join -S ROARK -D ADMIN -U awilliam
Password:
Joined domain ADMIN.