I do not use Opera but I can ‘guess’ some answers:

  1. the email must be processed first by avast (that is why you must use 127.0.0.1 or localhost for your POP3 and SMTP server) and then by your email client.

  2. you do not have to delete poplisten and smtplisten values. They will be used if your email client does not provide these values for email checking.

  3. you must write that configuration in the account settings of Opera and not at avast4.ini file. The username and password are not included in the avast4.ini file but at Opera.

Hope this help.