And why should I read from F-Secure and other competitor’s web-sites about such exploits (this is what Google returned at first)

http://www.f-secure.com/v-descs/classloader.shtml

As I understood from there: there is all because of the problems in the Internet Explorer and there is no harm done but virus still get downloaded but cannot activate

It is what said on that page. Is it true?

Thanx in advance (and would be nice if avast can catch the virus on the fly)