Hi,
First problem is that Form Wizard Pro requires mojoPortal 2.3.4.5 or higher as indicated on the system requirements tab
http://www.mojoportal.com/form-wizard-pro-product.aspx
But really that would not prevent installation, it just will throw errors when you try to use it. When you say you copied the file, that does not sound right. You should unzip the package and then copy the contents of the wwwroot folder in the package into the root of your web site.
You should first upgrade to mojoPortal 2.3.5.4 and review release notes in our blog for versions between your current version and the newest one.
Hope it helps,
Joe