The following instructions apply only to PC Study Bible Version 4. If you have Version 3, see KB551.
This "not authorized" message is usually caused by an unfortunate glitch during the installation of the program, or a file that was corrupted or mistakenly deleted. It has nothing to do with the registrations status of your program.
The quickest and easiest way to solve this problem is to remove and reinstall the software, per the instructions in KB705.