There seems to be a lot of chatter on the web about Avast reporting false positives on installers built with InnoSetup. I haven't found a lot of information on how to resolve it.
https://forum.avast.com/index.php?topic=183576.0
Also, DDSPF20 and DDSPF21 requires .net 4.8, so if the installer is having issues downloading that file you may want to do it manually by going to the download site:
https://dotnet.microsoft.com/download/dotnet-framework/net48 or direct to the web installer at http://go.microsoft.com/fwlink/?LinkId=2085155