It turns out that both pip and easy_install have trouble with the Paver 1.0a1 package. I’m going to look into that, but in the meantime I have removed the Paver 1.0a1 tarball from the cheeseshop so that people don’t accidentally get it. Sorry about that!
As a side note, it is unfortunate that easy_install and pip both will pick up alpha and beta releases in preference to release versions. I would think that a nicer default would be to prefer the current release version unless there’s a flag saying “give me the test release”.