Possible NATS issue.
 

This issue only comes up for me when visting nats driven affiliate areas so I am assuming it is a nats issue.
Whenever I am in the promo tools area (banners, zips, so on) and I am attempting to download content zips. It will never allow me to download more than one file at a time. I do the right click and save as and first one starts just fine. If I try to start a second I always get an "server returned an error or invalid response" message, or it just hangs there until the first file is completed.

I think these servers are set to accept X connections from an IP at time. I have noticed this with a few affiliate programs as well, some will allow 2 or 3 but not more than that.

I don't think nats has any bearing on how many downloads you can have open at any one time.

At first I wouldnt think so, yet oddly it is only happening at nats ran sites.