Can’t join to a Win2k Domain from W2Kw/s

I have W2 Adv server with AD, DNS & DHCP services.
In AD is computer object, with ws1 name.
When I tried to change from “Member of Workgroup” to “Member of Domain”, I got the error message:
The following error occured attempting to joing the domain “ddd.ccc.bbb.aa”:
The network path was not found.
Pls help me to solve the problem.