The SPNComboInst.exe creates a driver for the Softree hardlock.  

If you are using password protection you do not need to run SPNComboInst.exe.

Installation

1) Download the SPNComboInst.exe into a directory (see comment below).
2) Double click on SPNComboInst.exe and follow the instructions.

By default SPNComboInst.exe creates and installs the drivers in a default directory.  
It is recommended that you install the drivers in either c:\Program Files\Softree\RoadEng\Drivers
(or c:\Program Files\Softree\Terrain\Drivers).