Some time ago there was an issue about permissions (trying to control escalating privileges issue), not being able to access the avast folders, files, but that problem was resolved with program update some time ago.
What is the version of avast home you are using, 4.7.982 is the latest/current version ?
I have no problem opening it with notepad or any other text editor that I have, wordpad, editpad lite, etc. There are also no ASCII characters in it only plain text links to the servers. See image, I have obscured the urls but they are plain text also.