I meant to say before I actually fixed my problem by deleting my tekkit folder, running the launcher though the .tekkitlauncher file and then using the rec builds. Thanks for alp your help and concern.
I have the same problem as Woodrow and followed the instructions given by Backplauge exactly, yet when I tried to join a server, the problem still happend. If anyone knows how to solve this, please tell me. I would be greatful.