Seems the software cobolds are now at your place
For access to the log files right click on Avast blue ball, select Avast! Log Viewer - there You are able to browse the log files.
For direct Access the log files are located at:
C:\Programme\Alwil Software\Avast4\DATA\log (at least in my installation - default folder, German W2000)
To Increase log level, edit the avast4.ini file and set
LoggingLevel=20
(thats in the common section)
BTW - are You running any spam filter application or any other software which is scanning mails beside Avast ??
br
Peter
PS : have to do my morning walk now with my 2 dogs - so I'll be back in about 2 hours