In case you haven't see it, here's Apple's troubleshooting steps for error 1611 (from http://support.apple.com/kb/TS3694):
Error 1611: This error may indicate a hardware issue with your device. Follow the steps in this article. Alsoattempt to restore while connected with a known-good 30-pin Dock Connector cable, computer, and network to isolate this issue to the device. The MAC address being missing or the IMEI being the default value (00 499901 064000 0) can also confirm a hardware issue. Out-of-date or incorrectly configured proxy or security software, such as FoxyProxy, can cause error 1611. To troubleshoot third-party security software, follow these steps.
i had the 1611 error on my 3g.
it has been buggin me for about 6 months.
durring a restore the progress bar on my phone would get half way or sometime no distance before getting a 1611.
I tried and I tried to fix it over the last 6 months.
this is how I got around it today.
I used a short cable (about 15cms) to connect my phone to my Imac. I removed excess usb devices.
I did the "#" before GS.APPLE.COM thing in the host file.
tried several restores and always 1611.
then while doing other stuff (I'm trying to study for exams at the moment) my Imac had a kernal panic and shut down.
When I restarted I tried a restore and it worked and my 3g is back to life.
a fluke? lucky? a combination of cable/#gs.apple.com/restart?
I don't know, but my phone works.
note- I didnt go into DFU mode as my home button is broken. I didn't uninstall anything.
I had same problem. Lucky for me I found a post that said
Step 1. Turn off your iPhone.
Step 2. Hold down the power and after exactly 0.5s-1s press the home button.
Step 3. When you see the Apple logo, release the power button but continue holding the home button down.
Step 4. Open iTunes and wait for it to tell you that its in restore mode.
Because he does not say release home button I did not so kept it pressed continuously. (tired thumb)
First time I did this it went to error 9. Second time it said it had restored to factory settings & then went back to restore mode. Third time I did not keep finger on home key, it worked and is like a new phone.
Keep trying and you will win.