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^ That was me, I didn't log in before posting that comment.
I can confirm that it crashes when running that installer which can be downloaded by going to http://www.chris-pc.com/download.html.
I am also getting that offer in the English version of the DirectX Web Installer.
The "Include Google Chrome" checkbox is unchecked in an English language version of its installer. What language are you running its installer in?
Its not possible to do what you're asking since it requires lots of effort in order for it to be able to do it. In a similar post I made, the developer stated that Unchecky only automatically clicks the radio/checkboxes and assumes that a prompt when clicking Accept instead of Deny is good enough to get the user to not install the offer.
RaMMicHaeL: Try the installer that you can get by going to http://www.anvir.net/downloads/anvirrus_mainpage.exe.
Don't forget to make an extension (or userscript) that can do the same on Opera.
The image you posted isn't showing up. Please fix it.

Try using http://www.cacert.org/ to get a digital certificate for it.