[Samba] can't add samba to the domain

[MOU DONGYING]

 Hello,all

        I can't add samba to the domain with the command net join, the
error is like this:

net join -U usrname -S *****
Enter usrname's password:
[2009/03/26 11:03:55,  0]
utils/net_rpc_join.c:net_rpc_join_newstyle(393)
  Error in domain join verification (credential setup failed):
NT_STATUS_INVALID_COMPUTER_NAME
  
Unable to join domain **.

I can ping the domain server and nslookup is OK.

And the machine name with samba has been added to the domain list and
can be found.

the environment is : solaris5.8+samba3.2.4
the smb.conf is like this:

[global]
      workgroup = ***
      security = DOMAIN
      password server = ****
      log file = /usr/local/samba/var/log.%m
      max log size = 0
      os level = 65
      create mask = 0775
      security mask = 0775
      directory mask = 0775
      directory security mask = 0775
      block size = 4096

[test]
     comment = test share directory
     path = /tmp/test
     read only = no

Is there any one can help me on this?

Thanks

BR
May