iPhone 3GS user on iOS 5.0.1 . Trying to update to 6.1.2 using ipsw file

iPhone 3GS user on iOS 5.0.1 . Trying to update to 6.1.2 using ipsw file. Getting error 3194, tried on 3 different laptops same error. Any ideas why? Do note that I am unable to update to 6.1.3 as apps that was made by my company needs the iOS to be at 6.1.2.

I have tried the steps given in the Knowledge Base for error 3194 such as renaming the host file, checking the security and such.