Have you tried running RB as administrator?
This can help avoid permissions type issues, which your problem may be caused by (could not open the file c:\users...)

Right click the icon and select Run as Administrator ..
If this works, you can go to the right-click-properties window and in one of the tabs tell your computer to 'Always run as administrator'.


Make your sound your own!
.. I do not work here, but the benefits are still awesome