I had some troubles even installing this build (Swift 1.2).
Firstly, the version of LlamaKit that cocoapods installed wasn't compatible with Swift 1.2 (which RAC3.0 is currently targetted at).
I tried the manual install next, but it seems like there's a step missing. If you get some issues like "No such module Result" or "No such module Box", the solution is here - you have to add more than just ReactiveCocoa.xcodeproj. I filed an issue and the Readme is updated to explain this now.