There is a new(?) bug in Mac OS X that Java Web Start files (with extension jnlp) are not recognized and you get prompted to download them rather than launch them with Java Web Start. We have identified the following workarounds:
When trying to run the sensitivity calculator, web-based RTD, or the Correlator Graphical Setup (CGS) you get the message asking what you want to do with the jnlp file, change the Open with: to /System/Library/CoreServices/Java Web Start. This should then launch the applications correctly.