在我配置 MCF 后执行以下命令时遇到以下错误：
sunmatoMacBook-Pro-2:~ sunshiguo$ cf target
target: http://api.telemetry.cloudfoundry.me
sunmatoMacBook-Pro-2:~ sunshiguo$ cf register
/Library/Ruby/Gems/1.8/gems/interact-0.5.2/lib/interact/interactive.rb:569: warning: Insecure world writable dir /usr/local in PATH, mode 040777
Email> /Library/Ruby/Gems/1.8/gems/interact-0.5.2/lib/interact/interactive.rb:571: warning: Insecure world writable dir /usr/local in PATH, mode 040777
Email>
Email>
Email>
Email> ssg188550@gmail.com
Password> ******
Confirm Password> ******
Your password strength is: unknown
Creating user... FAILED
NoMethodError: undefined method `add_user' for nil:NilClass
For more information, see ~/.cf/crash
sunmatoMacBook-Pro-2:~ sunshiguo$ cf login
target: http://api.telemetry.cloudfoundry.me
NoMethodError: undefined method `prompts' for nil:NilClass
For more information, see ~/.cf/crash
请问这些错误是由什么引起的？怎么解决？