Hi there!
I just answered you on the other post you created. The plugin is not broken. You probably do not filled the plugin parameters properly. This error means that the plugin is trying to get a value from a plugin parameter but it somehow can't.
My guess is that you leave something in blank. So please, answer me back on the topic you created on the plugin page. Make sure you have filled every plugin parameter according to the instructions. And do not leave anything blank, unless the plugin parameter description says you can do it.
If the problem still happens, send me a screenshot of your plugin parameter so I can take a look.
Also, all the plugins are always updated to work on the latest version of the RPG Maker. You probably need to update your RPG Maker code too.