You don't need the 64-bit version of WinUAE; unless you're setting huge amounts of RAM i.e. 512MB plus for OS 4.1...
Download / extract the
32-bit version of WinUAE to somewhere on your hard drive.
Download the
Windows (32-bit) - Version 5.1 of the SPS .IPF plugin, open the archive, go into the "capsimg_binary" directory and extract "CAPSImg.dll" to where you extracted WinUAE to.
Done
