it spins for a while then says http error.
Are you a seller or a buyer? What exactly you are trying to download (meaning is it delivery, files sent by a buyer in order requirements or in a message, attachment on buyer request, etc.)?
I ask because the solution might be different for those. There seems to be a great variety of bugs when it comes to attachments and they all are different depending on the kind.
The OP appears to be a buyer.