New to Java

Hi ,
I am new to this forum as well as new to java...i created an applet application but getting an error start:applet not initialized..I searched for this topic in other threads also but could not find the correct solution that can resolve my error...So I need help..I have been struggling with this problem but got no solution :(
Exact error I am getting is:

C:\Program Files\Java\jdk1.6.0_13>appletviewer Slot503.html
load: class C:/Program Files/Java/jdk1.6.0_13/bin/Slot503.class not found.
java.lang.ClassNotFoundException: C:.Program Files.Java.jdk1.6.0_13.bin.Slot503.
class
at sun.applet.AppletClassLoader.findClass(AppletClassLoader.java:210)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.applet.AppletClassLoader.loadClass(AppletClassLoader.java:143)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at sun.applet.AppletClassLoader.loadCode(AppletClassLoader.java:690)
at sun.applet.AppletPanel.createApplet(AppletPanel.java:785)
at sun.applet.AppletPanel.runLoader(AppletPanel.java:714)
at sun.applet.AppletPanel.run(AppletPanel.java:368)
at java.lang.Thread.run(Thread.java:619)

Thanx a lot in advance