I've not seen Antivir crash, but that's certainly not acceptable. I doubt that it's incorrectly installed (you've tried it enough times). I also presume that you don't have renmants of other antivirus software still loading. It'll be a software conflict of some sort. From that message I can see that it's Win9x, which is quite prone to that sort of thing.

It may not be easy to solve, unless it's something running in the background that can be eliminated. Especially nowadays when many things you install may change versions of older system files. Also, device drivers can cause those kinds of conflicts in Win9x.

You should not use the program unless that one gets solved.

(The delays during updates and seeming loss of responsiveness when you click cancel, I feel were due to servers not responding rather than a problem with the program. If you wait long enough it should time out and cancel and then you should be able to click the 'x' to close it)