First you should do as the error says.
Second the most common solution to many errors is to delete you cashe, cookies and session.
You may do that via your browser but the best method would be to use the free program cCleaner from piriform
Their free version works very well. Just make sure you uncheck the install Avast AV too, when installing. Unless you want their free AV too.
Any other errors that may occur and you do not understand, you may contact admin about.