This should not happen and as Tim said, the cause version incompatibility between the installed version of Distributions and Julia 0.2.X.
Our Package system has great support for version requirements, but it is a manual process to ensure that one update requirements before tagging a new release that depends on new APIs, and it is sometimes forgotten. Please open an issue on https://github.com/JuliaLang/METADATA.jl/issues/new and ping @ivarne, and I might remember to fix it tomorrow. In the mean time you might try Pkg.pin to manually use older versions of the package. Updating to 0.3 is still recommended, but we should not break people's Julia 0.2.X installations on Pkg.update like this regardless.
