DOCBOOK-APPS: sealing violation?

[Dave Pawson <daveP@dpawson.freeserve.co.uk>]

win2000, saxon 6.22, 1.42 stylesheets.

Error reported:

I:>java  -cp \sgml\files;\myjava\saxon622.jar;\sgml\nw\docbook\xsl
\extensions\saxon61.jar com.icl.saxon.StyleSheet   -o tmp.fo  file.xml  \
\sgml\xsl\book\mybook.xsl "saxon.extensions=1"
Exception in thread "main" java.lang.SecurityException: sealing violation
         at java.net.URLClassLoader.defineClass(URLClassLoader.java:234)
         at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
         at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
         at java.security.AccessController.doPrivileged(Native Method)
         at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
         at java.lang.ClassLoader.loadClass(ClassLoader.java:297)
         at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:286)
         at java.lang.ClassLoader.loadClass(ClassLoader.java:253)
         at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:313)
         at com.icl.saxon.StyleSheet.<init>(StyleSheet.java:43)
         at com.icl.saxon.StyleSheet.main(StyleSheet.java:62)

Anyone any clues please?
AFAIK I've stripped out the http references to stuff,
which is all on my hard drive.

Confused, DaveP