Are you a computer administrator?

Right click on RealTimeStatTracker, go to security. Is Everyone listed with Modify, Read & Execute, and Write? There can be more checked, but those are the important ones.

Our installer should set those permissions on that folder. You may want to reinstall the program.
You can manually set the permission too by clicking edit, add 'Everyone', set full control.

This may be your problem. RTST may not be able to launch rtst_run_dx64 which in-turn can't load rtst_d3doverlay_x64.