If you don;t understand an error, the first thing to do is google it:
Can’t Add Script - The script don't inherit a native class that can manage a script. - Google Search[
^]
2.7 million hits on that one error message ... follow a few links, and see what you can find out ... we can't do anything to help based on the information you have given us: Remember that we can't see your screen, access your HDD, or read your mind - we only get exactly what you type to work with.
In future, please try to do at least basic research for yourself instead of wasting our time and yours?