Well, I'm back again. Miss me? ;)
RU has been updated to 2.0.0.0. That's right, it's world breaking time! (Sorry. :( )
Due to major Forge changes, 1.5.* worlds can't be transferred to 1.6.*. With that in mind, and the fact that FTB appears to be skipping it entirely, the 1.6.* support is yet...