Same here, but with an en-us installer. Seems like the inf file has gone missing? Rolling back to http://download.ff.avast.com/mac/vps9/vps915120900.inf in a browser gives a proper response, can’t figure out how to apply that info to fix this issue though…
Tried calling support but only got stupid answers like “there’s nothing wrong on the Avast site, it must be on your pc”. The log error quite definitely shows that the .inf-file is not there, but yesterdays file is when I check in my browser.
Hope someone here can help, otherwise I will retry tomorrow.