account migration from samba-tng to samba3

[Marianna]

Hi, sorry for my bad english, I'm an italian girl.
I have a problem: I have old server with samba-tng 0.3.2 with ldap 2.0.27
support and samba 2.2.8 installed. I want to migrate all accounts from
this old server on new server with samba 3.0.20 and ldap 2.2.28 support installed.
Can you help me???
I try with command "net rpc vampire -S oldserver" but result is
Fetching DOMAIN database
[2005/10/26 14:23:38, 0] rpc_client/cli_pipe.c:rpc_api_pipe(570)
rpc_api_pipe: cli_read error : 0/0
Failed to fetch domain database: NT_STATUS_UNSUCCESSFUL
thanks Marianna