Outpost's self protection will be stopping it.
The files mentioned are also the signature files (obviously unencrypted) being detected by avast, exclude the files from being scanned.
Standard Shield, Customize, Advanced, Add and
Program Settings, Exclusions
Personally I have the OP Pro, anti-spyware plug-in disabled, I have other anti-spyware applications that take care of that, it also is very active at boot (scanning hundreds of files) extending the boot duration. Not only that because it wants to open files for scanning, avast also scans them duplicating scanning effort.
But it is your system and choice.