Impulse uses HTTP&HTTPS connections, so it's strange that it cannot download (do they use a proxy and have rules specifically for Impulse?). I would contact [email protected] to see if there is a way to make it work.
As a workaround, if you really need to update the game and cannot wait for support's answer, you can go to http://anywhere.impulsedriven.com/, enter your Impulse username/password and select Demigod in the list. You will have to download the full game installation (all 2.82G of it) as there is no "patch" support in Impulse Anywhere at this time. This should get you updated until support can look at your problem and hopefully allow you to use Impulse normally.
n3crosys: having the latest version won't allow pirates to play online with normal customers. They only will be able to play single player/lan. If anything, this will stop them from contacting the old server infrastructure when the game starts. And since IIRC they have activation turned on in patched versions, they will need to workaround that too
