Do you experience problems during downloading?
Check your connection in Status and Interface settings window.
Use Test Server in Config > Servers.
We will probably ask you to do a test using only basic settings.
Do you experience problems during repair or unpacking?
Enable +Debug logging in the Status and Interface settings window and share the relevant parts of the log here using [ code ] sections.
It is an ipv6 issue, the operating system should decide whether localhost = 127.0.0.1 or localhost = [::1] (shortened). Opera doesn't seem to ask the operating system which ip localhost should go to and just assumes 127.0.0.1. Not quite sure why.