Excluding parts of the system aren't really a valid long-term workaround.
But you may never get relief if you don't report the false positives back to Avast, and it now seems to be easier to do than it used to be.
If you don't get prompts that lead you through it, get into the Virus Chest and submit from there.
For a while it was doing the same thing for me, by the way, reporting some kind of Evo:Gen problem, but that seems corrected.
-Noel