Applet java.io.FilePermission exception

Applet java.io.FilePermission exception

I have a Java applet for an intranet site which needs to access the file
system on the client's PC (specifically a LAN share). This applet has a
function similar to:
JSObject win;
public void init() {
win=(JSObject) JSObject.getWindow(this);
win.call("appletMsg", new Object[] {"<b>Applet Loaded</b>", "win"});
}
public void saveFile(String filepath, String filename) {
File theDir = new File(filepath);
try {
if (theDir.exists()) { // This throws exception
win.call("appletMsg", new Object[] {"Directory Exists", "win"});
}
else {
win.call("appletMsg", new Object[] {"Creating Directory...",
"msg"});
if (theDir.mkdir()) {
win.call("appletMsg", new Object[] {"Directory Created",
"win"});
}
else win.call("appletMsg", new Object[] {"Directory Creation
Failed!", "fail"});
}
}
catch (Exception e) { // This exception is caught
win.call("appletMsg", new Object[] {"Error Reading Directory!",
"fail"});
win.call("appletMsg", new Object[] {filepath, "fail"});
}
// More code for working with files, error happens above this
}
Javascript behind the applet
// call applet method
function save() {
document.myApplet.saveFile('\\\\LOCATION\\DIR\\DIR\\', 'test.txt');
}
// output responses from applet to div
function appletMsg(response, type) {
document.getElementById('output').innerHTML+='<br><span
class='+type+'>'+response+'</span>';
}
Troubleshooting/Thoughts:
the applet worked before I made the JS call the Java method (arguments
were in param lists, applet was fully reloaded when needed, file
operations were in init() method, reverting to this works but is terrible
practice)
the applet is signed with a self-cert
I put a JFileChooser in the init() method to make sure paths were right,
moved it to the saveFile() method and the dialog does not show. It doesn't
cause a JS error to show like it did with the .exists() call in Java, it
does throw a FilePermission exception in a try/catch
since this works in init() and not in saveFile() I can only assume this is
to prevent JavaScript itself from accessing the file system??