Now the Dutch have said "nee" as well...

This can mean many things:

Such as the fear of a strong central power government
Many Europeans are put off the expansionist EU
Western Europe is put off by immigration of its poorer eastern members
Smaller nations like the Netherlands fear being a junior member to France and Germany
Resentment because of the Euro (the dutch voted against the Euro yet it still became their currency)
And several other issues...

But most importantly, it means that the Euro is finally using value against the dollar and I will be able to afford to travel to Europe again! So vote "no", "non", "nee", "nein" whatever it takes!