The FTB Forum is now read-only, and is here as an archive.
To participate in our community discussions, please join our Discord! https://ftb.team/discord
If you watch the yogscast yogcraft series(particulary Duncan's), you'll notice that he says they had to convert world(alter data values) to solve the compatibility prob(which is probably the problem you're facing. You may have to destroy the blocks w/ the same data values as ftb in tekkit(like...