I've just established that by breaking the amount of data to be downloaded to create an archive into smaller sizes it works. But I'm unable to download an archive of the whole of the documents on my site at one go, which I was originally trying to do.
Is there a means of downloading the Assets Library as an Archive, in case an item gets deleted accidentally?
I've done some fixes in the 'download archive' code. There was a problem whereby it could generate two files with the same name. It should hopefully work OK now.
There still seems to be a problem if you're downloading a very large archive (many hundreds of megabytes) that the server will get confused and return an error. I don't understand why this is because all the code seems fine and a larger file isn't really any differerent to a smaller one!
Anyway, all being well you'll now have a bit more success with the archives!