My understanding is that Wilders call to ban the Quran was made in order to force a comparison between it and Mein Kampf, which has been banned in the Netherlands for several years under existing law. However, he has apparently amended his position since then, making it very clear that he believes in absolute free speech. He says so in no uncertain terms right here:

digitaljournal.com

I’m also somewhat startled at the tone of this post… . the British governement has just publically capitulated to terroristc threats originating from within the leadership of its own muslim community - and all we do is lament that Wilders is “wrong too?”