Operation Weserübung failed?

Operation Weserübung was the German codename for Nazi Germany's assault on neutral Scandinavia during World War II. The name translates as "Weser Exercise," the Weser being a German river.

http://en.wikipedia.org/wiki/Operation_Weser%FCbung

What if the Royal Navy had been able to stop the German forces and Norway was not invaded by Germans.

Would it have meant that Hitler could not have attacked France later on? Would it have also meant serious loss in iron ore shipment even if ships could bring their cargo from Southern Sweden?
Would the allied enter Sweden after helping Norway to stop the iron ore shipments to Germany?