Ok, I'm sorry, I was feeling attacked after the first few posts, so I read yours out of context, I'm afraid. Thank you for clarifying what you meant.
I'm glad to know that k9 makes an effort to work with Avast. Hopefully that means that if we find there's something they need to change, they will be willing to work to do so.
To try to give a bit more polite of a response, Eddy: when K9 says they give malware protection, what they're talking about is nothing like what Avast does. They don't do any scanning of any files on the computer. They don't even scan files being downloaded. All they do is block websites that are known to contain a lot of malware. They are strictly an internet filter, so none of the concerns raised in that kaspersky article should be a problem.
The conflict is clearly happening with Avast's Web Filter. If I leave that disabled, I never crash. When I enable it, the computer usually crashes within a few minutes if I start browsing. I hope this has helped clarify why K9 is not an anti-virus program and shouldn't have any problems running together with Avast.