Hi, I had an applet that ran well before, but today when I check, it doesn't run, the following error message is given, please help.

Java Code:
java.lang.reflect.InvocationTargetException
	at com.sun.deploy.util.DeployAWTUtil.invokeAndWait(Unknown Source)
	at sun.plugin2.applet.Plugin2Manager.runOnEDT(Unknown Source)
	at sun.plugin2.applet.Plugin2Manager.createApplet(Unknown Source)
	at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
	at java.lang.Thread.run(Unknown Source)
Caused by: java.security.AccessControlException: access denied (java.io.FilePermission C:\Users\MyComputer\Documents read)
	at java.security.AccessControlContext.checkPermission(Unknown Source)
	at java.security.AccessController.checkPermission(Unknown Source)
	at java.lang.SecurityManager.checkPermission(Unknown Source)
	at java.lang.SecurityManager.checkRead(Unknown Source)
	at java.io.File.exists(Unknown Source)
	at java.io.Win32FileSystem.canonicalize(Unknown Source)
	at java.io.File.getCanonicalPath(Unknown Source)
	at sun.awt.shell.Win32ShellFolderManager2.createShellFolder(Unknown Source)
	at sun.awt.shell.Win32ShellFolderManager2.getPersonal(Unknown Source)
	at sun.awt.shell.Win32ShellFolderManager2.get(Unknown Source)
	at sun.awt.shell.ShellFolder.get(Unknown Source)
	at javax.swing.filechooser.FileSystemView.getDefaultDirectory(Unknown Source)
	at javax.swing.JFileChooser.setCurrentDirectory(Unknown Source)
	at javax.swing.JFileChooser.<init>(Unknown Source)
	at javax.swing.JFileChooser.<init>(Unknown Source)
	at square.<init>(square.java:22)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
	at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
	at java.lang.reflect.Constructor.newInstance(Unknown Source)
	at java.lang.Class.newInstance0(Unknown Source)
	at java.lang.Class.newInstance(Unknown Source)
	at sun.plugin2.applet.Plugin2Manager$12.run(Unknown Source)
	at java.awt.event.InvocationEvent.dispatch(Unknown Source)
	at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
	at java.awt.EventQueue.access$000(Unknown Source)
	at java.awt.EventQueue$1.run(Unknown Source)
	at java.awt.EventQueue$1.run(Unknown Source)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.security.AccessControlContext$1.doIntersectionPrivilege(Unknown Source)
	at java.awt.EventQueue.dispatchEvent(Unknown Source)
	at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
	at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
	at java.awt.EventDispatchThread.run(Unknown Source)
Exception: java.lang.reflect.InvocationTargetException