Hi,
I am trying to reproduce your issue with the information you provided.
OS: Win8.1
Avast: 2014.9.0.2021 (Avast Free)
NVDA: dowloaded from http://community.nvda-project.org/wiki/Snapshots (“Thu Jul 31 09:27:55 2014” version)
But everything works OK, tray icon is accessible and the options are read correctly. Self-defense module is turned on.
Do you have any other screen readers installed? Or perhaps another antivirus?
Make sure your settings look like in settings.png and let me know. 