On Vista, isPluginInstalled returns false though deploytk.dll is installed with kernel jre bundle

Tested OS : Vista
Tested bundle : http://j2se.east/plugin/1.6.0_05-nightly/2007-08-30.23_28

Steps to reproduce :
1. Install kernel jre bundle
2. Uninstall the jre
3. check whether the deploytk.dll is copied under windows/system32 folder
4. Now launch http://web-east.east/www/tests/getjava/6529645/f1.html on IE
Getting the message "Detected that plugin was not installed"

Expected behavior : It should display "Detected that plugin was installed"
This happens only on vista with kernel bundle. With classic bundle, it is working fine.
On XP, both bundles are working fine.
This is completely reproducable on any vista machine if no other jres are installed on the machine. (dosn't happen if there are older jres)
1.) uninstall all JREs from a vista machine.
2.) install 6u10 kernel bundle, the registry key HKCR/CLSID/{CAFEEFAC-DEC7-0000-0000-ABCDEFFEDCBA} is there, and isPluginInstalled() returns true.
3.) uninstall 6u10 kernel bundle, the registry key HKCR/CLSID/{CAFEEFAC-DEC7-0000-0000-ABCDEFFEDCBA} is not there, and isPluginInstalled returns false.