You should make sure that you have the application pool that the website your forum is using is running in 32bit mode.
You can change this by editing the app pool in IIS Manager and under Advanced Settings you will find 'Enable 32-Bit Applications', which needs to be set to 'True'.
This gives better performance, memory usage, and also allows Classic ASP components to run.
We use the 32bit version of AspUpload on Windows 2008 R2 boxes, but I believe that the 64bit version installs both 32 and 64 bit versions. However, if you have installed the 64 bit version and Web Wiz Forums still can not see it after changing the app pool to 32 bit mode you should un-install the 64 bit version and install the 32 bit version instead.