Changing an "ALLOW" setting to "BLOCK"

I just installed comodo and really love it; within minutes of installation, I got a notice that “cloaker.exe” was trying to get to the command prompt!

I have avast av, and when I first got the comodo balloons informing me of connections being made, I unconsciously allowed a couple of them.

They were both related to my av; one said avast was trying to access the internet and on said avast was trying to alter a registry key.

Since I knew avast, I allowed them and the box was checked to remember the setting.

But it strikes me as odd that avast would want to alter a registry key.

Should I be concerned and, if so, how can I change the setting?

Also, what do we think of avast, anyways?

Thanks

With trusted antivirus like avast, there should be no concern, let it change registry if it likes.