Slow speed on local network

Hello everybody,
I have a strange problem on my network. We have Windows NT 4.0 Server and we
are part of a big European WAN with its domain, but we have also runing a
local domain. If we are loged on the local domain, the speed is fine, but if
we log on under the global domain, the speed is incredibly slow (only about
200kB/s). This problem has started after the datacenter migrated to a new
WINS server, but all other European locations are running fine and all the
admin in the datacenter are telling me that WINS is configured fine.

Is anybody able to help please?

Thanks,

Petr