Hi Martin,
Have you checked QuickBooks to see if there's something that needs your attention? Usually when I see that message its because the Method Integration Engine certificate hasn't been set or there's something that needs to be set before the connection continues. Check to see if there's something flashing on your taskbar.
Something else to consider is any firewall that might be blocking the sync engine. If you have a firewall (I believe Norton comes with Windows 8), disable it and see if the sync will start.
- Adam