If you are receiving this message, you may not have the correct permissions required modify your system registry. You need to have admin rights on the system. If you already have admin rights, you may have a problem with permissions in the registry key below:
HKEY> LOCAL MACHINE> Software> Carlson Software> Carlson Software> R2004
To check, go to Start> Run> type regedit and browse to the above folder. Right click on the R2004 folder, select Permissions and make sure Admin as Full Access toggled on.