Rick,
Let me explain what this variable does. If you open a dialog like Draw Patterns, it has a "symbology" dialog that can be opened to allow the user to set the symbology of their pattern lines. When you open it, it will be set to a certain level, color, style and weight - whatever the defaults are. Without the variable being set, you would have to select your level, then MANUALLY set Color = ByLevel, Weight = ByLevel and Style = ByLevel. With this variable set, when you select a level the Color, Weight and Style will AUTOMATICALLY set themselves to ByLevel. But note that you have to select a level.
You should be able to use the following variable to have the DTM tools load a standard .lpf file.
GPK_DTM_LOADDEF
Derricke