This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Non-static methods -- i.e., regular instance methods -- have to have an object of the class to operate on. Static methods don't need an object. Therefore, you can't call a non-static method from a static one without creating an object. Here's an example of code that will cause this error message: