使用Netbeans和Swing部署在Netbeans中创建的Applet的错误

I've created an Applet with NetBeans. My partner used NetBean's Drag-and-Drop Swing editor for the interface. It runs perfectly fine with no exceptions or warnings when I right click on the applet file and click "run". However, it throws this exception when I build it and put the NetBeans generated html file on the apache server on my machine and run it. I've created an Applet with NetBeans. My partne