The first thing is that you have to do some configuring of both Java and Safari to get the applet to run at all.
Once that was all done, I could log in from all my Macs, fire up the applet and establish a secure connection. I made sure that the Safari and Java preferences were set the same on each machine but still no joy.
To fix things for the moment I simply removed the jdk folders.
And then checked that the reported version of Java was 1.6 on each Mac.
Then I remembered the difference between 'System' Java, Java plugins, and Java development kits.
Web applets still use the up to date, secure version 1.7 plugin.
Simply put, you can have multiple versions of Java in different places.
What was happening on the not-working Macs was that the jdk versions were being used, and the Juniper vpn client won't work with them.
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