DNS problem, nslookup works, ping doesn't

I am setting up a development server in my flat. I have set up an Ubuntu DNS server on it and have added the zone weddinglist (just weddinglist - no TLD. It’s just an internal domain.)

This works fine on my Ubuntu laptop.

On all my Windows PCs (Vista and XP) I get the following from the command prompt:

C:\Users\Giles Roadnight>nslookup weddinglist
Server: UnKnown
Address: 192.168.0.40

Name: weddinglist
Address: 192.168.0.41

C:\Users\Giles Roadnight>ping 192.168.0.41

Pinging 192.168.0.41 with 32 bytes of data:
Reply from 192.168.0.41: bytes=32 time<1ms TTL=64
Reply from 192.168.0.41: bytes=32 time<1ms TTL=64
Reply from 192.168.0.41: bytes=32 time<1ms TTL=64
Reply from 192.168.0.41: bytes=32 time<1ms TTL=64

Ping statistics for 192.168.0.41:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds: Minimum = 0ms, Maximum = 0ms, Average = 0ms

C:\Users\Giles Roadnight>ping weddinglist
Ping request could not find host weddinglist. Please check the name and try again.
My ipconfig:

C:\Users\Giles Roadnight>ipconfig -all

Windows IP Configuration

Host Name . . . . . . . . . . . . : Giles-Desktop
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Hybrid
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No

Ethernet adapter Local Area Connection:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Marvell Yukon 88E8001/8003/8010 PCI Gigabit Ethernet Controller
Physical Address. . . . . . . . . : -----
DHCP Enabled. . . . . . . . . . . : No
Autoconfiguration Enabled . . . . : Yes
Link-local IPv6 Address . . . . . : fe80::f179:680f:f313:5448%8(Preferred)
IPv4 Address. . . . . . . . . . . : 192.168.0.5(Preferred)
Subnet Mask . . . . . . . . . . . : 255.255.255.0
Default Gateway . . . . . . . . . : 192.168.0.1
DNS Servers . . . . . . . . . . . : 192.168.0.40
NetBIOS over Tcpip. . . . . . . . : Enabled
I am pretty sure that I have the DNS set up OK as the nslookup is OK but I can’t ping and I can’t access webpages at weddinglist.

How can I make ping work for the Windows PCs?