[Samba] Unable to access Samba Domain Member

[Nicholas Fechner]

Hi,
I'm trying to connect to a Samba Domain Member, but I always end up with 
the same strange error.
The PDC (authenticating againt LDAP) and the server itself (Lobo) are 
Samba 3.0.2a-1 (Debian). I first
tried to connect from my Windows client. It gave me the following error:
"\\Lobo is not accessible. The specified network name is no longer 
available."

When connecting via smbclient I get:
xyz:~# smbclient -U nfechner \\\\lobo\\software\\
Password:
session setup failed: Call returned zero bytes (EOF)

With Log Level 3, I always get the same error message:
[2004/02/26 11:41:29, 3] libsmb/namequery_dc.c:rpc_dc_name(143)
  rpc_dc_name: Returning DC SAVANNAH (192.168.200.3) for domain PONTON
[2004/02/26 11:41:29, 3] libsmb/cliconnect.c:cli_start_connection(1337)
  Connecting to host=SAVANNAH
[2004/02/26 11:41:29, 3] lib/util_sock.c:open_socket_out(710)
  Connecting to 192.168.200.3 at port 445
[2004/02/26 11:41:30, 3] rpc_parse/parse_lsa.c:lsa_io_sec_qos(181)
  lsa_io_sec_qos: length c does not match size 8
[2004/02/26 11:41:30, 3] auth/auth.c:check_ntlm_password(219)
  check_ntlm_password:  Checking password for unmapped user 
[PONTON]\[nfechner]@[SAVANNAH] with the new password interface
[2004/02/26 11:41:30, 3] auth/auth.c:check_ntlm_password(222)
  check_ntlm_password:  mapped user is: [PONTON]\[nfechner]@[SAVANNAH]
[2004/02/26 11:41:30, 3] smbd/sec_ctx.c:push_sec_ctx(256)
  push_sec_ctx(0, 0) : sec_ctx_stack_ndx = 1
[2004/02/26 11:41:30, 3] smbd/uid.c:push_conn_ctx(287)
  push_conn_ctx(0) : conn_ctx_stack_ndx = 0
[2004/02/26 11:41:30, 3] smbd/sec_ctx.c:set_sec_ctx(288)
  setting sec ctx (0, 0) - sec_ctx_stack_ndx = 1
[2004/02/26 11:41:30, 3] smbd/sec_ctx.c:pop_sec_ctx(386)
  pop_sec_ctx (0, 0) - sec_ctx_stack_ndx = 0
[2004/02/26 11:41:30, 3] libsmb/namequery_dc.c:rpc_dc_name(143)
  rpc_dc_name: Returning DC SAVANNAH (192.168.200.3) for domain PONTON
[2004/02/26 11:41:30, 3] libsmb/cliconnect.c:cli_start_connection(1337)
  Connecting to host=SAVANNAH
[2004/02/26 11:41:30, 3] lib/util_sock.c:open_socket_out(710)
  Connecting to 192.168.200.3 at port 445
operation is not possible without initialized secure memory
(you may have used the wrong program for this task)

Any help would be appreciated. I already reinstalled the samba and 
rejoined it to the domain.
Tnx in advance,
Nicholas