I'm that guy and this is the thread you refer to. http://line6.com/support/topic/21282-customtone-upload-assistance-please/
I own the Helix Rack, run Win 7 and have a similar issue in Chrome, IE and Firefox. It certainly seems like a Windows issue. I have been driving myself bonkers trying to figure this out, thinking it was a problem on my end. Please fix this Line 6. Being able to share our tones and interact as a community is vital.