samba - Jul 2008 - Joining RHEL5 server as member of win2003 domain fails - RHEL4 works

Dear SAMBA experts,

I have several RHEL4 servers where samba is working perfectly with the exact
same configuration file as is the case for this RHEL5 server, but on RHEL5 I
cannot join the domain controlled by a win2003 server.
>From running the following command this is extracted:
[root@skade ~]# net rpc testjoin -d5
---
[2008/07/04 15:06:35, 5] rpc_client/cli_pipe.c:check_bind_response(1701)
  check_bind_response: accepted!
[2008/07/04 15:06:35, 10] rpc_client/cli_pipe.c:cli_rpc_pipe_open_noauth(2277)
  cli_rpc_pipe_open_noauth: opened pipe \NETLOGON to machine FRVLAN30 and bound
anonymously.
[2008/07/04 15:06:35, 5]
passdb/secrets.c:secrets_fetch_trust_account_password(294)
  secrets_fetch failed!
[2008/07/04 15:06:35, 5] passdb/secrets.c:get_trust_pw(695)
  get_trust_pw: could not fetch trust account password for domain FRVLAN
[2008/07/04 15:06:35, 0] rpc_client/cli_pipe.c:get_schannel_session_key(2449)
  get_schannel_session_key: could not fetch trust account password for domain
'FRVLAN'
----

Can you give me a hint of where to look for misconfiguration. 

This the minimal configuration of smb.conf which works on RHEL4 to testjoin -
It's not working on RHEL5.
[global]
netbios name = skade
workgroup = frvlan
server string = skade running %v
security = domain

Version of samba on RHEL5 is: 3.0.25b


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