Trouble with one plugin

Running X-3b Pro and everything works great but when I open a X-2a project I get a message saying one plugin is missing. The plugin is there. I can right click the effects bin and add the plugin so its there. And the weird thing is when I open the same project in X-2a Pro now I get the same message. Ive uninstalled and reinstalled the plug but no change. The plug is DMG Equilibrium. All other plugs work fine. Any ideas?