I have the same issue. I did a fresh windows 7 install and still have the problem once on a while. Sometimes it saves no problem sometimes I get the error. The LSP forum couldn't help because they couldn't duplicate the error on their machines... Kind of a weird one. I learned to live with it
I actually have both installed in the same location and I have not had a issue yet. Granted I am only play with it this year and not actually sequencing a show but I have probably about 20 hours with no issues.
I did make one change and that is I changed the shortcut to start as administrator since it was asking me the question every time I started up.