You might check out this KB http://support.apple.com/kb/TS1275
It contains the following section:
Error 1611: This error may indicate a hardware issue with your device. Follow the steps in this article. Also attempt 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 Out-of-date or incorrectly configured proxy or security software, such as FoxyProxy, can cause error 1611.