Can please help me?

I have tried to upgrade my iPhone 4 (GSM) from iOS 4.2.1 to 5.0.1. Here are the steps I followed:

1. Downloaded an Apple certified version of IPSW for iOS 5.0.1.
2. Set my iPhone into DFU mode using the latest version of iREB tool (iREB-r5).
3. Changed the server link in the HOST file to point to 74.208.105.171 gs.apple.com.
4. Re-opened iTunes (latest version 10.6.0.40).
5. Shift+Restore to browse to the 5.0.1 IPSW.
   
   Kept getting error 3194 when iTunes attempted to restore the firmware, so I then tried the following:
   
6. I used TinyUmbrella (v5.10.07) and unchecked the box 'Set Hosts to Cydia on Exit'.
7. Removed all server links from the host file and then started TSS server on TinyUmbrella (of course I saved and closed the Host file before launching TinyUmbrella).
   
   But still the same error popped up.
   
   I then attempted the following:
   
8. Created a custom firmware using Sn0wbreeze (v2.9.1).
9. Then tried to restore the custom firmware from iTunes, but I was also running TSS server using TinyUmbrella.
   
   It went a bit further, but I got error (2005).
   
10. Restarted the laptop (Windows 7 64-bit).
11. Uninstalled/re-installed iTunes.
12. Restarted laptop.
13. Tried both firmwares again (the original IPSW and the custom firmware) - SAME ERROR (either 3194 or 2005).
14. Used another laptop (Windows 7 64-bit) and repeated the same steps.
    

No matter what I do I cannot get anywhere with it (very frustrating). Of course I don't want to upgrade to iOS 5.1 directly from iTunes because I want to use the untethered jailbreak for iOS 5.0.1.


N.B. I checked that my iPhone in DFU so many times using iREB and it confirmed that it is in this mode!

AM I MISSING ANYTHING?

Thank you

Now with APTicket/APNonce introduced by Apple, it's no longer easy to restore. This may help: Frequently Asked Questions - JailbreakQA

i had a similar problem few weeks ago on win64bit, and i tried editing hosts file, replacing usb cable, and finally i solved the problem by re downloading the file and creating anew copy of custom FW with Sn0wbreeze, and it worked with TinyUmbrella,

Is this a major issue when Jailbreaking now or have the issues been resolved?