Can't join Tekkit servers, Minecraft Forge error?

[Naretule]

Whenever I try to join a Tekkit server I get an error message saying, "To connect to this server you need to have Minecraft Forge installed."

My friend is playing on the server with the same Technic client, and I've double checked multiple times that I'm running Tekkit.

I've connected to the server before, but have never had this problem until now.

I've re-downloaded the client multiple times, and even tried adding Minecraft Forge to Tekkit manually, just to have the client crash.

Any help?

Edit: I've changed the manual Tekkit build to the most recent update, but it still won't connect.

[The_DarthMoogle]

Proper report format pleaz!

Also, are you running mac? I've seen this problem before, and I'm gonna have a mooch around for you now.