Try one of the following solutions:
- Make sure you are using the latest version of the Motion Bro extension.
- Make sure you are using the latest release of a presets package.
- Run After Effects as an administrator, and then enter the purchase code.
- Disable the antivirus program or firewall for the time of entering the purchase code.
- Restart After Effects.
You may have unpacked the preset package into a system folder (such as Program Files).
If so, try unpacking the presets in a different (non-system) directory on your disk.
Then in the extension panel, click “Change Path” and select this directory.
If the problem appeared after updating the presets pack, check this update guide: