Well ... remember what I said ...
I wanted to get you a workaround that would let you have all your providers running. Please give me a little while to check out Script Blocking (I use the Home edition and we humbler souls do not have Script Blocking) I think lukor understands what we have been doing here and he may chime back in on that.
So, this is just a workaround to get you out of the "sometimes it works sometimes it doesn't" situation and keep you going for now. I need to do a little research but I will be back and ask you to run a diagnostic function that I hope you will feel able to do and post the results back here.
From this testing I believe that you do, in fact, have some software running on your system that played well with the intercepting of browsing with avast 4.7. However, with avast 4.8 due to some timing changes sometimes it does and sometimes it does not. We need to find out what that is and try to find a permanent solution that will remove the need for the proxy.
But ... it is now past 2am here in California and I need to get some sleep. I hope that you are now in a configuration that will keep you going until I can get back to this later today.