The installer placed it in the wrong folder. Manually copy RSMB.aex and RSMB_Support.aex from C:\Program Files\Adobe\Common\Plug-ins\7.0\MediaCore\REVision to your custom plugin folder.
Accepts external motion vectors (such as those rendered from 3D applications like Blender, Maya, or Cinema 4D) to apply pixel-perfect blur to CG elements. ReelSmart Motion Blur RSMB v6.4.4.zip
Whether you're using version 6.4.4 or a newer release, RSMB is built on powerful, proprietary technology that automates a once-laborious process. The installer placed it in the wrong folder