Did you download from junolab.org? The latest verison(1.1.0) is at https://junolab.s3.amazonaws.com/release/1.1.0/juno-windows-x64.zip
from julialang.org/downloads . It is bundled with all the required packages and julia 0.4.3 . Your downloaded Juno version seems old and it was not bundled with required packages for older versions. I suggest using new version if you do not need julia 0.3 . If you willing you can also try Juno with Atom editor instead of Lightable derived one. New developmemt of Juno progresses around Atom editor. The link to the complete bundle is https://github.com/JunoLab/atom/releases/download/0.3.0/JunoSetup.exe from https://github.com/JunoLab/atom-julia-client/blob/master/README.md