GMod Server Issue - Help Appreciated

[SamMunRAWR]

Okay, what's happened is a doozy of a thing, because it's something I'm sure shouldn't be happening.

I've set up a separate machine connected directly to my router which is a Linksys WRT54GC, the files are set-up, the server runs fine, I'm only doing a ten slot at the moment so it's nothing too strenuous.

Here's the issue, when I try and even LOOK at the server info from my main computer, it crashes the server for anyone connected and seems to make it LAN only I think. So that I'll connect fine, everything works, plugins are fine, console on the server sees I've joined, but as soon as anyone else tries to join through my user game info on Steam, it'll show them the IP "192.168.1.105:27015".

...Which as we all know, wouldn't let them connect; however before then, they can connect fine as it even shows in the Master Servers list under the IP address of "92.234.237.14:27015"; same goes for the console on my server machine, it shows that it's connecting via that IP address and never shows it changing once the server starts. But once again, as soon as I try to join (or even look at its details) on my other computer on the same network, it'll crash for everyone else and only let myself join.

So could anyone give me some idea into what's going awry here? I'll be adding as many screenshots of settings as I can possibly give you and I'll list details of machine/network info below as well:

BASIC INFO
Server OS: Windows 7 Ultimate x86
Processor: Intel® Core™2 Duo CPU T5470 @ 1.60GHz
Ram: 1.5GB
Game(s): Garry's Mod
Start Up Command:
"@echo off
cd c:\srcds/orangebox
title Foxxy Fox - 100% Fox for 100% Snowmews.
:srcds
echo %time% - Starting game server (Sandbox Mode)...
echo NOTE: CLOSE THIS WINDOW BEFORE YOU SHUT DOWN THE SERVER OR IT WILL RESTART AUTOMATICALLY
srcds.exe -game garrysmod -console -port 27015 +sv_lan 0 +map gm_flatgrass +sv_defaultgamemode sandbox +maxplayers 10
echo %time% - srcds closed or crashed, restarting.
goto srcds"
Admin Mods: Exsto

NETWORK AND BANDWIDTH INFO
Bandwidth: Down - 9.08Mbps Up - 1.42Mbps
Router: Linksys WRT54GC
Local IP of Server: 192.168.1.105
External IP: 92.234.237.14
Port Forwarding:


Here's a screenshot of Port Triggering:


Network Info on the Server Machine:


DHCP List:


SRCDS Console Screenshots:




And now I'll just explain how my network is set up:
We're on Virgin Media, so it goes into a Cable Modem --> Linksys WRT54GC
--> Server Machine [192.168.1.105]
--> Main Computer [192.168.1.107]

The 'Main Computer' appearing to be the culprit of screwing up the server when I try and join any internet games on it. It's also listed in the server.cfg as "sv_lan" "0".

So any help anyone could give me as soon as possible on this would be much appreciated, and if it's enough to get it working, I'll repay you by making you an admin on the server should you wish to be one.