This error message has come up recently when trying to install Camtasia Studio. From researching the error it does not seem specific to just Camtasia Studio as other programs are running into the same exact problem. Here are the steps we found that seemed to resolve the issue.
Browse to the following folder.
Move the folder that starts with the S-1-5 to your desktop so it's no longer in the RSA folder. Then install Camtasia Studio and it should work. That S folder will be automatically recreated.