Hello,
I´ve installed Avast free (only the web shield) and set “ashQuick.exe” to integrate with Orbit Download Manager.
In parameters i wrote: /action:delete
If i understand it correctly, you installed only the web shield ?
In that case try and install and the file system shield, see if it makes any difference.(Control Panel-> Add/Remove Programs-> Repair Avast → Custom → Check File System Shield)