The folders in my library is empty

Hey there, just bought the new macbook pro and I have a problem. Im do alot of musicproduction and began installing the apple jam packs. Suddenly when I was half-way through a installation of a jam pack my computer ran out of battery. And now I cant install the the jam pack because the old "half-way-trough-installation" is blocking the new one. So, the problem I have is that the folder where the jam packs are supposed to be is empty, just like all the other folders in the library. Firstly, the library is hidden cause its moutain lion, but i fixed that, but now in my library, all the folders are empty. How do I fix that?