Budds, we can guide you...
See, did you click on 'Settings' in my signature?
There is the location of avast4.ini file (generally C:\Program Files\Alwil Software\Avast4\Data\avast4.ini).
Open it in your computer with Notepad. Or double click it...
Browse for the section [MailScanner] into brackets.
Add the following line:
UseAlternateRtfSyncing=1
Boot.
Does it work?