To make a long story short, I read a topic post stating that in order to fix the "game session is no longer available" error in the game, you need to type in your IP address to access your router information, and then set two ports, one with the port "3074" and the second port being "28960". In the post, it says that the second service's internal IP address needs to be set to your computer, but it doesn't specify where the first service's IP address needs to be set. I've tried setting the first port's IP to my computer, but that still gets the error.  (It needs to be set to a LAN IP).

Any help would be appreciated.

Very very odd, you don't have a cracked waw right?

It's not pirated at all. I library share it with an old friend on Steam but that wouldn't have anything to do with it. I was perfectly able to connect with SOME friends before I attempted to open the ports. Now it won't allow me to join those friends previously mentioned.

I've read comments on that forum and it seems like it's a successful fix for most people. It will only allow me to set the second Port Service IP Address to a LAN IP (Devices connected to the router only), but I'm not sure which device it needs to be under considering the second port service is already set to my PC.