Java Plugin has an extension mechanism that will enable applets to install system-wide extensions into the jre/lib/ext (e.g c:\Program Files\java\jre1.6.0\lib\ext) directory. That won't work for window Vista OS, as protected mode can't write there.
Posted Date : 2006-05-31 16:38:18.0

Actually, plugin itself dosn't write to the lib/ext directory.  The problem is that plugin is not allowed (unless running as administraitor) to call Runtime.exec() to launch the installer (which itself may write to lib/ext or wherever it wants).

For now we need to update the release notes to clairify this, and show a more meaningfull error dialog that informs the user why the installer cannot be run.
Posted Date : 2006-06-26 16:11:19.0

N/A

Currently the extension install in JPI will only works when you login window Vista as Administrator, for Administrator User or Standard User, it won't work.

The issue is not only related to write file to jre/lib/ext directory, it is before that, JPI don't have permission to create a bin/java process which needed to do extension installation. as extension install is a separate process as a new installation.

The window Vista has taken the new security model and won't allow low process (JPI in IE) to create a new process. See bug #6440902 for same issue.
Posted Date : 2006-06-20 18:37:03.0

We are going to show a error dialog box with the following text:
"Only Administrators can run extension installater in Window Vista"

for user to launch extension installer from Window Vista machine.
Posted Date : 2006-06-29 17:26:33.0