iPhone 4 update problem

My iPhone 4 offered me a firmware update (I can't see the version number anywhere) through iTunes almost two days ago but it never installed correctly. Ever since then, I've been trying to restore my iPhone and install the new firmware version but I always get the following error message "The iPhone 'iPhone' could not be restored. An unknown error occurred (9)." I've checked http://support.apple.com/kb/TS3694#error9; did not help. I've tried several different USB ports, two different cables (the other one from my iPad 2), two different non-Mac computers (desktop and laptop with up-to-date Windows 7) with two different up-to-date iTunes installations. Never had any problems updating my iPhone's firmware before and haven't installed any new security software in the past few months. My iPhone is basically bricked now and I'm not able to contact my reseller while traveling. Any quick fix ideas? Would be greatly appreciated.