I have two dc , one is w2k3 as primary DC (whith all
operation master) and other is w2k as secondary DC.
The two DC replycate regulary and there isn't any problem.

When i try to upgrade my w2k3 to sbs 2003 in the setup
requirments i see:

You must be a member of the Domain Admins, Schema Admins,
and Enterprise Admins groups. (i use an account that is
member of all of this group)

Unable to contact all domain controllers.

If you try to perfom this command from srv2k3 to srv2k0 :

net view //srv2k0
system error five has occourred
acces is denied

I try to perform this command whit the same
administrative account .
What can i see . Thank you and sorry for my english.