java applet grey in browser

i have an java applet, and when i start it it shows a
gray win with x. the console shows

java.lang.NoClassDefFoundError: GeomApplet (wrong name: vj3/GeomApplet)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:502)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:123)
at sun.applet.AppletClassLoader.findClass(AppletClassLoader.java:148)
at
sun.plugin.security.PluginClassLoader.findClass(PluginClassLoader.java:168)
at java.lang.ClassLoader.loadClass(ClassLoader.java:299)
at sun.applet.AppletClassLoader.loadClass(AppletClassLoader.java:114)
at java.lang.ClassLoader.loadClass(ClassLoader.java:255)
at sun.applet.AppletClassLoader.loadCode(AppletClassLoader.java:501)
at sun.applet.AppletPanel.createApplet(AppletPanel.java:566)
at sun.plugin.AppletViewer.createApplet(AppletViewer.java:1775)
at sun.applet.AppletPanel.runLoader(AppletPanel.java:495)
at sun.applet.AppletPanel.run(AppletPanel.java:292)
at java.lang.Thread.run(Thread.java:536)

my class file is in the same folder as the html page where i put
<APPLET CODE="GeomApplet.class" WIDTH="353" HEIGHT="207" VIEWASTEXT
></APPLET>

dose anyone know what's the problem


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