These error messages usually means that your DAW is trying to load an old version of the plug-in file, while the latest version of the binary file is in a different location that the DAW is not scanning. Please try this:
1. Search your computer for the following file(s) depending on which of the product that is giving you the error message:
Addictive Drums 2.dll
Addictive Keys.dll
RC-20 Retro Color.dll
XO.dll
Addictive Trigger.dll
DS-10 Drum Shaper.dll
Delete all files you find with these names.
2. Run the XLN Online Installer and let it repair your installation. This will ensure that only the correct plug-in file is left on your computer.
3. Click on Customize Installation in the Online Installer, click the Installation Paths tab and then note the VST 2 Plugins (64 bit) path.
The next step is to check the preferences in your DAW. The option is usually named "Paths", "VST paths" or "Plug-in paths". In those preferences, add the plug-in path from step 3 and then hit the Rescan button. After that, try loading your plug-in again. If you're still having problems with this or if you're experiencing this on macOS please contact XLN support.