Well
I had the "old" RegSupreme Pro installed in =>
"C:\Program Files\RegSupreme Pro"
and I have installed the RC1 in =>
"C:\Program Files\RegSupreme Pro RC1"
without any problems and I can run them separately.
Although there are issues when running Registry Cleaner of the RC1 I described in the beta-testing section of this forums (but this has nothing to do with the installation directories, because it seems to be a BUG of the program itself).