Here are some tips for troubleshooting.
- Do you have any version of Ruby installed? If you enter “ruby -v” on the command line, if it returns a message that begins with the word “ruby” and then a version number, you do have ruby installed.
- Do you have a recent version of ruby installed? If you enter “ruby -v” on the command line, it should returns a message that begins with the word “ruby” and then a version number that starts with at least “2”. If it starts with anything lower, you should update your Ruby installation.