This is a discussion on tiny umbrella "host file not writable" help within the iPhone Jailbreaking forums, part of the iPhone Hacking & Jailbreaking category; Have been trying to get my 3GS restored, having no luck at all.
One weird thing, when I open tiny umbrella it warns me to ...
Anti-Virus and anti-malware programs are also known to lock the hosts file as a protective measure (changing it is a popular attack for malware). Disable those temporarily and see if that helps.
If you are Windows7 you really shouldn't have too many problems. Vista was much more of a pain...
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