from what i gather on my google searches on the inter-tubes, it says that this error has to do with overload from the google servers. If you are trying to download the same apk several times from them, and they think you are spamming them, they will block your ip, account, or phone for a short while. Im not sure the method, but the only thing you can do is wait it out or get a hold of google directly as some users above have done.
i wish there was a simpler/more immediate solution for this as much as the rest of us.