I've set my Router to DMZ but it still didn't fix the problem. Oh well it maybe the case of waiting for PATCH 1.2 for a fix.. Sometime in the next 6months... NOT GOOD.. No Lan Party with Unreal 3... Back to good all Working Unreal 2004..
I've resolved my Lan problem, These are the steps i tuck to resolve my issue.
1) First Step make sure you have Patch 1.1. Now delete the profile which is located in MYDocs. (Note when you load unreal again it will prompt for CDKey again and you'll need to change any settings you changed)
2) 3 computers in total.
2a) Asus Computer
This computer has a total of 4 Network Devices. I disabled each device but my Network card which i use for the LAN gaming. (Also disabled my Vista Firewall).
2b) Aopen PC
This computer only had 1 Network Devices (Disable Vista Firewall)
2c) Dell Laptop
This Computer had 5 Network Devices Disabled all but my Wireless Network Device. (Disabled Vista Firewall).
3) Launch all Computer with Unreal3. Asus Computer HOST the LAN game. And the other computer found the lan game without any problem.
4) Went back into my settings on all my computers enabled all my Disabled Network devices and Vista Firewall. (All but my Dell Laptop could see that LAN Game).
5) Went back to my Dell Laptop disabled all the other Network Devices but my Wireless Network Device (Firewall still enabled). Can see the Unreal 3 Lan game now.
Now i'm not sure why this worked for me but it did, Also it improved my internet Gaming side aswell. Now and again if i'm unable to locate my LAN/Internet Unreal3 games i make sure i disable all my Extra Network Devices and DELETE the Unreal 3 Profile settings from MYDOCs, And it works again without any problem.
Hope this is some help.
A couple of my mates who where having crashing problem on some levels when playing on the Internet, Did the same and its looked to have resolved there issues by disabling any extra Network Devices and deleting the Profile Data from MYDocs.