Just to be on the safe side... WiFi can sometimes fool you.
Try going to repository with your browser:
https://downloads.maemo.nokia.com
You might get a warning about the certification. Just close the page/browser then. If it gets you there. It should work network wise. The bug is somewhere else.

Do you have any other type of connection that you could try? Some WiFi routers have tendencies to be tricky and mystic.