When I tested and reproduced the error, I uploaded from my hard
drive using the basic "upload file" feature in a document library
through the standard document library view (not the explorer view).
If you're asking for network type info - When I did the upload I did
it over a VPN from an office in the US to an office in Ireland. The
user who first produced the error was in the same office as the
server, so they used a basic LAN type connection.