The authors of IE Defender are claiming on CastleCops forum that their software is "clean and is real antispyware".
Talking about the problem of the trojan fake codec that advertise for IE Defender installation, they post:
we have a partnership for our distributors to advertise our program, we pay them a percent of registration fee. Some of them use illegal methods, that we not accept, our customers send us abuses about it and we closed some of our affiliates accounts without paying them. We are watching on it but there are problems with them sometimes. We're working on this problem and it's very sad for us.
Looking at the servers IP of IE Defender and the Trojan: they are the same. No more to say.