Cannot update iPhone 3GS from 6.1.2 to 6.1.3

Hi! I tried to update my iPhone 3GS's firmware from 6.1.2 to 6.1.3; however at the end of the update process, iTunes prompted "error 14", leaving my device into recovery mode.

I already tried the solutions listed on apple's support page (http://support.apple.com/kb/ts3694?viewlocale=fr_fr#error14) but it did not help 😟...

- I have USB 2.0 ports

- I do not have third party security software conflicts

- My internet connection is not behind a proxy

I tried to reboot my MacBook pro OSX Lion, restarted iTunes, and also tried to perform the update from another computer (a PC, Windows 7) with no luck.

Also, the following did not work:

- Downloading the 6.1.3 firmware (IPSW file) from iClarified and updating the device manually

- Restoring directly from iTunes: iTunes kept telling me at the end of the firmware download that the file corrupted

It is the first time that I an issue with my iPhone and I desperatly tried several times to solve this problem without getting a positive result... 😟 😟 😟

Any help or idea would be greatly appreciated.