drop linux, linux users don't use AVs anyway.
I'm very curious to see your "scan module", considering how much trouble you're having with this.
Who exactly is "evil AV" designed for? hackers? average end-users? system admins? I don't think you have a chance with any of 'em. Would rethink the name btw, may scare ppl off.
If this is simply a learning experience, then perhaps focusing on the UI and directory scanning is a mistake. Maybe you could start with a command line program that takes a PE file(exe, dll) as an argument. Then parses that file, to see if it's evil.