Please, try this:
1) Download the Dependency Walker
2) Run it from one the problematic render nodes.
3) Open Options->Configure Module Search Order
4) Click the Browse
button and pick your Max root folder.
5) Click Add Directory
to add the Max path to the list, and close the dialog with Ok
and pick ForestPackPro.dlo
from the Max "plugins" folder.
7) Once dependency check is completed, use File->Save
to save the results into a .dwi file and sent it to us.
Hopefully that should give us a clue about the problem.