nslookup "Can't find server name for address 184.168.221.20: no response from server"

To All,

I have installed Windows 2033 Enterprise Server (x64 Bit Edition) and installed both DNS (Both Forward & Reverse Lookup Zones) & Active Directory at present and I am having the issue below:

This is an CMD input from my Server:

Microsoft Windows [Version 5.2.3790]
(C) Copyright 1985-2003 Microsoft Corp.

E:\Documents and Settings\Administrator.REB01>nslookup
*** Can't find server name for address 184.168.221.20: No response from server
Default Server:  UnKnown
Address:  184.168.221.20

> rebenterprises.co.uk
Server:  UnKnown
Address:  184.168.221.20

*** UnKnown can't find rebenterprises.co.uk: No response from server
>

This is an CMD input from one of my clients:

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\Robert Brindle>nslookup
*** Can't find server name for address 10.10.10.1: Non-existent domain
*** Default servers are not available
Default Server:  UnKnown
Address:  10.10.10.1

> rebenterprises.co.uk
Server:  UnKnown
Address:  10.10.10.1

Non-authoritative answer:
Name:    rebenterprises.co.uk
Address:  97.74.215.7

>

I would be geateful for any further assistance in relation to this issue.

Regards,

reb999000.

P.S: I am using a Cisco 837 ADSL Router for my connection(s).