What version of Camera Raw are you actually running? Try (Help /) About Plug-in / Camera Raw.
I am using 8.6. Would very much appreciate your help.
If you have Camera Raw 8.6 installed correctly then you should be able to open the files from that camera. Did you check to verify that you are actually running Camera Raw 8.6 using Help/About Plug-Ins/Camera Raw from the Photoshop menu? And, is version 8.6 the only version listed?
Can you upload one of these raw files that don't work for you to a place like www.dropbox.com and post public download link to it? Either something is wrong/different with the files from your camera or something is wrong with the software on your computer. Being able to test a file on someone else's computer would help narrow down which.
FWIW, I can open a sample FZ1000 rw2 file in PS-CC2014/ACR 8.6 from here:
You might try downloading this specific image and see if it works for you or not.