On MAC OS X 10.8 platforms with the upgrade of Safari web browser to the latest version (6.0.3) brought by the latest MAC OS update (10.8.3), Java plug-in gets disabled. For enabling it users need to follow these steps:

• · visit Oracle's Java testpage in Safari: http://www.java.com/en/download/testjava.jsp
• · after a while an Inactive Plug-In message will appear
• · click on it and follow the instructions, you will get a Security Warning - grant permission to run the test

• At the end you should get a message that Java is working

We have also published this solution on the http://www.archicadwiki.com/RemoteKeyUpgrade/Troubleshooting site.