The program stores information about the default folder and other customization information in a file called flsplan.ini, in the following location:
Documents\Family Law Software\Flsplan\_fls\exe\system\temp
If the computer can not write to this location, then it would not be able to store the default folder and other customization information.
Check write permissions to this location.
If you are running the program from a network, try installing and running locally from that PC.