Jacsebalon

Well, I am not that familiar with hamachi, but if that doesn't work, it looks like you have two choices. Either try some other VPN program, or just port forward. I would go with port forwarding, personally. I do it all the time and it takes like 10 seconds. There are plenty of guides online (and even entire websites) dedicated to helping people in your situation. But Jay? has a point, here. If there is nothing wrong with Tekkit, then why are you posting on the Tekkit forums? It seems to me like the issue has nothing to do with Tekkit, but rather one (or both) of your connections. Or maybe one of you is using the incorrect version of tekkit? The server uses 2.1.1, maybe he updated to 3.0? More info from you would really help us help you, mate.

I'm unsure from your original post, but it sounds to me like you updated to Tekkit 3.0. If that is indeed the case, that's your problem right there. The server is designed for Tekkit 2.1.1. Go back to the recommended build (and tell your friends to as well) and everything should work. If that isn't the case, then I don't know what to tell ya. Some more specific information would've been fantastic, though.