I decided to write here, because my problem is somehow related with this question.
I  tried to make the fps-like level demo in applet, but some problems occur. When I'm compiling the demo on my machine, there is no problem - the applet is running, but when i try to load the applet from the web, nothing happens. Java Console shows the following errors:

ava Plug-in 1.5.0_05
Using JRE version 1.5.0_05 Java HotSpot(TM) Client VM
User home directory = C:\Documents and Settings\user


----------------------------------------------------
c:   clear console window
f:   finalize objects on finalization queue
g:   garbage collect
h:   display this help message
l:   dump classloader list
m:   print memory usage
o:   trigger logging
p:   reload proxy configuration
q:   hide console
r:   reload policy configuration
s:   dump system and deployment properties
t:   dump thread list
v:   dump thread stack
x:   clear classloader cache
0-5: set trace level to <n>
----------------------------------------------------

load: JPCTDemo.class can't be instantiated.
java.lang.InstantiationException: JPCTDemo
   at java.lang.Class.newInstance0(Unknown Source)
   at java.lang.Class.newInstance(Unknown Source)
   at sun.applet.AppletPanel.createApplet(Unknown Source)
   at sun.plugin.AppletViewer.createApplet(Unknown Source)
   at sun.applet.AppletPanel.runLoader(Unknown Source)
   at sun.applet.AppletPanel.run(Unknown Source)
   at java.lang.Thread.run(Unknown Source)
Exception in thread "Thread-4" java.lang.NullPointerException
   at sun.plugin.util.GrayBoxPainter.showLoadingError(Unknown Source)
   at sun.plugin.AppletViewer.showAppletException(Unknown Source)
   at sun.applet.AppletPanel.runLoader(Unknown Source)
   at sun.applet.AppletPanel.run(Unknown Source)
   at java.lang.Thread.run(Unknown Source)
java.lang.NullPointerException
   at sun.plugin.util.GrayBoxPainter.showLoadingError(U÷P?