There is certainly something wrong with your virus definition updates, whilst the streaming updates are working fine, the auto updates aren’t.

Are you getting any errors displayed to the screen on the virus definition auto update ?

When you try the manual update what error is displayed ?

I suspect it is saying that you should use the full update or words to that effect:

  • Manual update of VPS - avast! Virus Definitions Update - Manual Download VPS Update (virus definitions, vpsupd.exe, approx 103 MB). - Save the file to your hard disk, locate where you saved it and double click it and that should carry out the virus definitions update.

A browser isn’t required to complete the auto/manual updates, so the browser you have is irrelevant in this case. But is required to do the above download.