Ditto - I have the exact problem trying to update my iPhone 4 to iOS 5. I updated to iTunes 10.5 last night with no problems. Downloaded iOS 5 via iTunes this afternoon, got the same messages 3014 etc. and now iTunes won't recognize or recover my iPhone. Apple support page says I need to disable the firewall and any 3rd-party security, which I have done, to no avail. Did you find a solution?
iPhone 4, Windows 7, iTunes 10.5
Well after trying for 9 straight hours, I was finally able to get iOS 5 to work and update. In all honesty, the only thing I did differently was restart my computer. Now, I dont know if that is THE fix for all of these problems but after 9 hours, I was willing to try anything.
Once I restarted my computer, i started iTunes, plugged in my phone, got the usual error message that my phone needed to be restored. After that, it was smooth sailing from there. I just let iTunes and my iPhone do its thing and it restored and updated like nothing had happened. It even saved 99.9% of all of the stuff I had on my phone prior to the update. The .01% are safari bookmarks which werent a big deal. But all of my photos, contacts, app settings and evertything else was there.
Hope this works for you! Good luck.