The version you're likely looking for is . It was developed by The Foundry and is the most compatible version for the 64-bit architecture of After Effects CS5.
If you want to troubleshoot a specific you are seeing, let me know the exact text of the error and your operating system so I can give you the exact fix. Share public link after effects cs5 plugin keylight 12 download install
Verify that you placed the files in the Plug-ins folder, not the Scripts folder. The version you're likely looking for is
Open Windows Explorer and navigate to the following default directory: C:\Program Files\Adobe\Adobe After Effects CS5\Support Files\Plug-ins after effects cs5 plugin keylight 12 download install