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.
Both codebase and archive are relative paths, so they should not begin with "/" (which makes them absolute paths on Unix, and may not have any meaning on Windows).
I advise to keep all applet files in the same directory, and then to run it not within an IDE, but in a browser. It's easier to sort out classpath problems like these that way. Any error messages you get would end up in the Java Console.