have you started a new game after installing the script, or did you load an old savefile?
80% of all scripts require a new game, installing them makes old savefiles incompatible (with exactly those "undefined" or "nomethod" errors).
If this error happens on a new game, then either you made a mistake configuring the script (never paste and ignore, you need to read the script instruction and configure it after pasting it into your project), or you have two incompatible scripts.
I suggest you follow the link "how to use a script" in my signature, it teaches about how to configure scripts and how to find incompatible scripts in a project.
I've moved this thread to Script Support. Please be sure to post your threads in the correct forum next time. Thank you.