Hi and welcome to the forum!
The error message suggests that there is something wrong with the data you supplying ( Neuroticism) , but since we don't have your project file, we can't really see what might cause the error. Could you post a representative subset of your data, for example the output of dput(head(Neuroticism)), so that we can to reproduce your problem?
Just for completeness, here is a link to the forums homework policy so you can make sure that you are following all the guidelines there . More importantly, they also contain a bunch of links that explain how to ask your questions in the best way.