apple blocked by UAC ?!?

[newbie_jar]

i have a major problem with my applet, and i hope you guys can help me, or point me in the right direction..
my applet is designed to save some game files into users computer...
it works very well on computers sunning older os like windows XP or older versions of windows, works on linux, but when it comes to windows vista or windows 7 i face a huge problem.
if the user just double click on the Internet Explorer / Mozilla browser and visit my website, the applet get stuck after the user accept to run the applet and receive the following error in Java Console:

Provided by some users, the error code is like this:
java.io.FileNotFoundException: C:\WINDOWS\Fonts\marss_font.TTF (Access is denied)
at java.io.FileOutputStream.open(Native Method)
at java.io.FileOutputStream.<init>(Unknown Source)
at java.io.FileOutputStream.<init>(Unknown Source)
at fontapplet.fileUrl(fontapplet.java:81)
at fontapplet.fileDownload(fontapplet.java:65)
at fontapplet.start(fontapplet.java:18)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionR unnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
java.lang.NullPointerException
at fontapplet.fileUrl(fontapplet.java:96)
at fontapplet.fileDownload(fontapplet.java:65)
at fontapplet.start(fontapplet.java:18)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionR unnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Exception: java.lang.NullPointerException

First working scenario on windows vista or windows 7:
If the user starts the Internet Explorer /Mozilla browser by clicking mouse 2 and hit Run As Administrator, then visit my website, the application loads, then he accept the applet, the font get installed. No more warnings and nothing. Everything woks well...
The second working scenario with windows vista or windows 7:
User has UAC (User Account Control) turned off, or at the minimum level... again, the applet is loaded and executed correctly...

Any suggestion how to avoid this Access denied error?

[Norm]

Have you tried another approach using JNLP and Java WebStart?