OK, Got that to work and looks like it updated to 0401-9
I killed the avast.setup process, stopped the avast iavs4 Control service and followed your steps to set the proxy except I selected the box to use IE proxy settings. BTW, instead of "advanced" the wording is "details".
However, when I now go back to review the settings, when I click on the "Proxy" button, nothing happens.
I have since restarted the control service and changed the update setting to download automatically.
Burl