Assuming that you've finished the DMZ/Port Range Forwarding mess, your server should now be open to the world, or at least to whomever you've created a registered username and password to your server. Now i will go over how to (or at least how I) make sure it all works.
---Please note, that you may have problems doing this depending on what kind of security software you have running on your pc. I'm not familiar with most of these programs. A pretty simple example is for the Sygate Personal Firewall (personal fav freebie.) When you open the server for the first time, a window should pop up asking if you want to allow said program access to [internet (i forgot what words it uses.) In that window, click the little box to allow permanent access, then click yes.---
Get ahold of a second pc or enlist/bribe a guinea pig -erm... friend to give you some of thier time. If it isnt already there, download and install Teamspeak RC2 Client on pc#2. Open the client, click Connect>>Connect. In the Local Addressbook tab, you can hand enter each line of information, then click connect at the bottom. Doing it this way, there is a pretty high chance that something was enetered wrong, and you can waste attempt after attempt trying to figure out what is wrong.
The other way to do this is, in my opinion, more efficient and has less margin for error. Next to the Local Addressbook tab, click on the Web Server List tab. If you havent done this before, the Server List Filter should pop up. If it doesnt,click on Change Filter at the bottom of the page.
Leave all options in the Server List Filter window set to "Show All" except for, in the bottom left, click on "Show servers containing" bullet and put whatever you named your server in the text box. Click OK.
All servers online with whatever you put in that box as part of thier server name will pop up in the list window. Find your server in the list (should only be a few in there, if there's even more than one listing), highlight it, and click "Copy to Local Addressbook" at the bottom right of the window.
Back on the Local Addressbook tab, click on your server's name, and put in your nickname. If you're allowing anonymous users, enter the server password, if any, and any other relevent information, and click connect. If you are registering each user yourself on the server's administration page, click on the "Registered" bullet in the client window, enter your login name and user password, along with any of the other relevent information and click Connect.
If all information is correct, you'll hear "Link Engaged" chime from the client, and boom!, you're on. If something is wrong, you'll hear an "Error" chime, and you'll see a little half-witted guess at why the client thinks it couldnt connect to the server.
Here is where using the server list can be a godsend to your watch. If the server shows up in the list, but you are unable to connect, then you know that there is a problem with the client side login information. Well that, or the information was entered wrong into the server administration page. If your server does not show up in the window, you can assume the problem is server-side.
Looking now at the PC which has your server on it, right click on the server icon in the taskbar. Now mouse over "Your IP's". You should see two addresses in here. One is your network address (192.168.1.xxx), the second should be your ISP's (Internet Service Provider) provided address (something other than 192.168.1.xxx). If you only see the network ip, recheck all of the information you entered into the router... basically start form the very top of my ramblings here, and hopefully you wont read this part again. If you see both numbers, you now know that your network settings are good, you have a software problem.
With both addresses showing, your server is visible on the net, but something is blocking the streams. To check this, reboot your pc, go to lunch, open your task manager once windows gets around to fully loading and close all non-essential programs including your security suite. Now load up the server, right click on the icon, and again mouse over "Your IP's", make sure you have both numbers. Back on the client, try to login. if you still cant connect, reboot the client PC and clear all non-essential programs from task manager, then load client and try again.
If you've made it this far, all i can suggest is email tech support, or *shiver* looking towards Roger Wilco.
-Good Luck (^_^)