I too am having this exact same issue!
I’ve just had to reinstall everything as my hard drives died, but I decided to reinstall Win7 64bit and install Cubase 64bit
everything has gone perfectly fine, apart from this hiccup!
rx2 files worked fine before, when I had Cubase installed as 32bit on the 32bit OS I was running
I’ve looked everywhere and tried everything I can think of - is there a fix for this issue!?
when I go to import a rx2 file it just says “Invalid or not supported file”
then when you click “open” it continues to say
“Error: Medium type not supported or invalid medium!”