First thought: It sounds like TH3 isn't installed in the directory where the CA-X chain plugin is looking for it.
When I clicked on that same TH3 button, it opened up an instance of the plugin.
See if you can find any settings menu for the CA-X amps modules, to find out if there's a directory setting.
Or click on the Online Info button to see if you can find out what that error code means.