If you are getting an message across the bottom of the screen when you go online, then it's probably a setting in the webshield.
Click the "a" icon, click on the webshield provider. Click the customize button, then the advanced tab. Uncheck "Show detailed info on preformed action".
If you have the pro version of avast, it could be the script blocker splash screen you are seeing. You can turn that off by following the above steps, but click on the webshield provider. On it's advanced tab, uncheck "Show spash window on startup".