Can't launch Java Cache Viewer by "javaws -viewer" if set user.cachedir to a no-permission dir

Steps:
=====
on win_xp
1.Install jre b48 PIT from /net/dig-dug.east/bigtmp/deployment/1.6.0/pit/2005-08-11.14_37
2. Clean user and system cache ( if has setup system cache )
3.Setup system cache ( deployment.system.cachedir )
4. Using control panel, set the user cache to a location that the user has no permission to access
5. Launch Java Cache Viewer use command : javaws -viewer
Exception thrown :
JNLPException[category: System Configuration : Exception: null : LaunchDesc: null ]
    at com.sun.javaws.Main.continueInSecureThread(Unknown Source)
    at com.sun.javaws.Main$1.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)

But Java Cache Viewer can be launched by ControlPanle-->View