:O ok this usually fixes is.
Hamachi is evil. It took me half a year to figure out that it was causing my PW-multiplayer to be broken. Better uninstall it from the computers.
If you are using normal LAN after that, it should work.
You can also forward any TCP port in your router to a host and host the game on that machine on the specified port.
It's also important not only to install, but also LAUNCH the same versions of the game. You can check the exact version in the options menu at the bottom. (Something hopefully containing BoosterPack1)
I'll uninstall Hamachi from both computers, and if it still doesn't work I'll try changing the CDs keys, since I'm suspecting I've might have accidentally written down the same CD key for both games
. Not sure about this though, which is why I'll try uninstalling Hamachi first.
And yes, every time I have made sure to launch the same version of both games, so that shouldn't be an issue here. Thanks for the help anyways though
. We'll see what happens when I try this out.