What are these multiple "Avast Encounters Error" messages ?
avast isn't a content filtering program, it is looking for virus content rather than adult content.
I'm trying to read between the lines here and I believe you may be saying that you are getting either redirected to adult web sites or getting pop-ups of adult sites ?
If so these are browser hijackings, usually adware. There are a number anti-adware/spyware tools that you might want to add to your defences.
If you haven't already got this software (freeware), download, install, update and run it, preferably in safe mode.
1.
Ad-Aware2.
Spybot Search and Destroy3.
Spywareblaster Don't install this until you are clean.