Clearing your cache is a good thing to do every so often.
Web browsers save tiny files onto your computer when you visit websites. This means the next time you view those websites, they'll load faster. This is what techies call 'caching'.
Club Penguin updates with new content every week and sometimes a web browser will load old content that was cached (saved) rather than new files. This is known as a 'cache error'. It can cause slow loading and login, and can display old content instead of new content.
Ask an adult to help you to clear your cache.