Thanks you for using our software
You don't need to install the license on the render slaves, is not used. There must not be problems, but if you don't like to have inactive licenses on disk, remove the "<licensenumber>.sls" file from C:\Documents and Settings\All Users\Application Data\Itoo Software\Licenses
Perhaps for the next release we will include a "Slave render" option in the installer.
Btw, the only files needed for slaves are:
* The distribution maps from "C:\Program Files\Itoo Software\Forest Pack Pro\distmaps\images", that can be copied to any texture folder
* And of course, the tree textures
(more info about Forest files: http://www.itoosoft.com/english/menu.php?id=forest_install
All these files can be installed on network paths if you configure 3DS to use them (as shared plugins, Mental Ray shaders and textures).