You need to downgrade to the initial FtB release. The update that they did for servers actually removed some (Extra Bees) content, so we are waiting for them to re-add it before updating the server.
http://www.nerdorbit.com/forum/m/6035323/viewthread/4956618-how-to-downgrade-your-ftb-portal-gun-142v02-extra-bees-14
Try that out and see if it works. Someone linked that to me as a solution. Not 100% it will work, but it might.