samba - Apr 2004 - Can not leave active directory domain (Red Hat Enterprise Linux ES 3.0 server)

I can use kinit to get kerberos ticket. I used my AD domain user
account(NOT domain administrator, but can join Win2K server to AD realm)
and I could do "net ads join /company/ad/level/Computers -U my_username
-S Win2K_AD_DC1", the following is the output:

[2004/04/07 18:54:41, 0] libads/ldap.c:ads_add_machine_acct(1086)
  Warning: ads_set_machine_sd: Unexpected information received
Using short domain name -- REALM_NAME
Joined 'MY_SERVER_NAME' to realm 'REALM_NAME'

But I can not do "net ads leave /company/ad/level/Computers -U
my_username", it says "Failed to delete host 'ERD-TT-WORKFLOW'
from the
'REALM_NAME' realm."

I also could not do "net ads testjoin".

Anyone has any idea on this?