[pathfinder_nick]

I had the same issue with a build of 8.1 when trying to upgrade. I had to physically take the switch to my HQ (45 minutes away) in order to get it to pull the download. Our switch was a 50V. However I believe they fixed the issue once you got to a certain build of 8.1 (Sorry, can't remember which build). They gave the switch more time to complete the FTP download before timing out. We completed an upgrade from 8.1 to 9.1 about 3 weeks ago with no issues upgrading the 50V across the WAN. We were on build 13.25.3804 of version 8.1 before upgrading to our current 9.1 build.