Comment 7 for bug 338785

Yes, i did.
At this moment, this bug doesn't affects me, upgrade and full reboot of my computer helped to get it work.
I assume, it were happened, becouse other firefox copy has been started in background that downloaded files (this behavior is achieved with extra addition to firefox), but i'm not sure about it.
Anyway, i think i t will be better to avoid such thing's during updates of system. It really bad when updates are run in backgorud, and such errors halt your work.

If any more information is nessary, feel free to ask me for it.