I just tried the same thing in safari 5.1.2 as well as IE9.0.8112.16421 in each mode from developer tools (IE9, IE8, and IE7)

I was able to access the files using your link before and while logged in, and also after logging out. It's very strange that this problem seems to randomly affect only some of us now. I guess it's reassuring that it's at least working for some of us.

I wonder if Google is using different rules for different combinations of IP blocks and User Agents? This would make sense if they were experiencing problematic bot activity posing as IE from a certain IP range. Maybe? Just a guess really.