[Samba] Samba 3 as domain member of w2k realm

[R.B.]

Hi Guys,
i've a problem joining a samba 3.0.7-1.3E.1 in a w2k domain:

[root at proxynode2 squid]# net ads join -U myuser
myuser's password:
[2004/11/18 13:29:32, 0] utils/net_ads.c:ads_startup(183)
  ads_connect: Program lacks support for encryption type

I've also changed the Administrator's password for key generation...
what can i check? I have a similar server in the same net that works fine.

Thanks
Riccardo