What are you using for the power supply?
Just curious, I have a whole box full of PC fans from old scrap computers...I work at a computer company.
I tried it with computer fans but could not get any of the 8 or 9 old phone adapters ect. to work because of the AC/DC conversion.

So I ended up buying 120v Fans from RadioShack that I could just wire a normal plug on the end. They work great