If you do not have any use for a program, then you should uninstall it.
Adobe Air is on your system, if you don't want it uninstall it and avast won't prompt you to update an out of date program that could leave you vulnerable to exploit. On my win7 system I only found out I had Adobe Air through the update notice and promptly uninstalled it.
If you read the avastUI, Support, Program Help it tells you why:
Malware often spreads by exploiting known security issues in commonly used software. This means if your software is kept up to date, most malware would be unable to spread!
